Peacock Engineering | IT Support & Computer Repair

// IT Toolkit

Scripts, References & Troubleshooting

Handy IT resources, quick-reference commands, scripts, and troubleshooting guides for common issues.

🪟 System Info & Diagnostics

# System information

systeminfo

msinfo32

# Check Windows version

winver

ver

# Hardware details via WMI

wmic cpu get name,currentclockspeed

wmic memorychip get capacity,speed

wmic diskdrive get model,size,status

# Battery report (laptops)

powercfg /batteryreport

🔧 Repair & Maintenance

# Run as Administrator!

# System File Checker

sfc /scannow

# DISM repair (online)

DISM /Online /Cleanup-Image /RestoreHealth

# Check disk (schedule)

chkdsk C: /f /r

# Fix boot record

bootrec /fixmbr

bootrec /rebuildbcd

# Reset TCP/IP stack

netsh int ip reset

netsh winsock reset

⚡ Performance & Process

# List running processes

tasklist

tasklist /fi "imagename eq chrome.exe"

# Kill a process

taskkill /f /im notepad.exe

# Disk cleanup

cleanmgr

# Startup programs (PowerShell)

Get-CimInstance Win32_StartupCommand

# CPU/Memory top processes

Get-Process | Sort CPU -desc | Select -First 10

👤 User & Security Mgmt

# List local users

net user

# Add/modify user

net user username password /add

net localgroup administrators username /add

# Enable hidden Admin account

net user administrator /active:yes

# Flush DNS & renew IP

ipconfig /flushdns

ipconfig /release && /renew

# Windows Firewall status

netsh advfirewall show allprofiles

📋 PowerShell Quick Scripts

# Get all installed software

Get-ItemProperty HKLM:\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\* | Select DisplayName, DisplayVersion | Sort DisplayName

# Find large files (>100MB)

Get-ChildItem C:\ -Recurse -ErrorAction SilentlyContinue | Where Length -gt 100MB | Sort Length -desc | Select FullName,@{n='MB';e={[int]($_.Length/1MB)}} | Select -First 20

# Pending Windows Updates

Get-WindowsUpdate

# Export Wi-Fi passwords

netsh wlan show profiles

netsh wlan show profile name="WiFiName" key=clear

📁 File & Registry Ops

# Robocopy (backup/mirror)

robocopy C:\Source D:\Backup /MIR /LOG:backup.log

# Take ownership of folder

takeown /f C:\folder /r /d y

icacls C:\folder /grant administrators:F /t

# Backup registry key

reg export HKLM\Software\key backup.reg

# Search registry

reg query HKLM /f "searchterm" /s

# Environment variable

setx MY_VAR "value" /m

🔍 Network Diagnostics

# Ping with TTL

ping -t 8.8.8.8 # Win continuous

ping -c 4 8.8.8.8 # Linux

# Traceroute

tracert google.com # Windows

traceroute google.com # Linux

# DNS lookup

nslookup google.com

nslookup google.com 8.8.8.8 # Specific DNS

# Check open ports (local)

netstat -ano # Windows

ss -tulpn # Linux

🌍 IP Subnet Reference

CIDR	Subnet Mask	Hosts	Usage
`/8`	255.0.0.0	16,777,214	Class A
`/16`	255.255.0.0	65,534	Class B
`/24`	255.255.255.0	254	Class C
`/25`	255.255.255.128	126	Half C
`/26`	255.255.255.192	62	Quarter C
`/27`	255.255.255.224	30	Small
`/28`	255.255.255.240	14	Very Small
`/30`	255.255.255.252	2	P2P Link
`/32`	255.255.255.255	1	Host

🔌 Common Ports Reference

Port	Protocol	Service
`20/21`	TCP	FTP
`22`	TCP	SSH / SFTP
`23`	TCP	Telnet insecure
`25`	TCP	SMTP
`53`	TCP/UDP	DNS
`67/68`	UDP	DHCP
`80`	TCP	HTTP
`110`	TCP	POP3
`143`	TCP	IMAP
`443`	TCP	HTTPS secure
`445`	TCP	SMB / Windows Shares
`3389`	TCP	RDP
`3306`	TCP	MySQL
`5432`	TCP	PostgreSQL

📡 Wireless Standards

Standard	Name	Max Speed	Band
`802.11b`	WiFi 1	11 Mbps	2.4 GHz
`802.11g`	WiFi 3	54 Mbps	2.4 GHz
`802.11n`	WiFi 4	600 Mbps	2.4/5 GHz
`802.11ac`	WiFi 5	3.5 Gbps	5 GHz
`802.11ax`	WiFi 6/6E	9.6 Gbps	2.4/5/6 GHz
`802.11be`	WiFi 7	46 Gbps	Multi-link

🧮 IP Subnet Calculator

Network Address—

Broadcast Address—

Subnet Mask—

Wildcard Mask—

Usable Host Range—

Total Usable Hosts—

🐧 System Commands

# System info

uname -a # kernel info

lsb_release -a # distro info

cat /etc/os-release

# Hardware

lscpu # CPU info

lsmem # Memory blocks

lspci # PCI devices

lsusb # USB devices

df -h # Disk space

free -h # RAM usage

uptime

📦 Package Management

# APT (Debian/Ubuntu)

sudo apt update && sudo apt upgrade -y

sudo apt install package

sudo apt remove package

apt list --installed

# YUM/DNF (RHEL/CentOS/Fedora)

sudo dnf update -y

sudo dnf install package

rpm -qa # List installed

# Snap / Flatpak

snap install package

flatpak install flathub com.app.name

👑 Users & Permissions

# Users

id # Current user info

whoami

cat /etc/passwd

sudo adduser username

sudo usermod -aG sudo username

# chmod permissions

chmod 755 file # rwxr-xr-x

chmod 644 file # rw-r--r--

chmod +x script.sh

chown -R user:group /dir

# sudo logs

grep sudo /var/log/auth.log

🔍 Process & Service Mgmt

# Process monitoring

top # or htop for better UI

ps aux | grep process

kill -9 PID

pkill -f processname

# Systemd services

sudo systemctl status nginx

sudo systemctl start|stop|restart nginx

sudo systemctl enable nginx # autostart

sudo systemctl list-units --type=service

# Logs

sudo journalctl -u nginx -f # follow logs

sudo journalctl -p err -b # errors this boot

Click any issue to expand troubleshooting steps:

🐌 Computer Running Slow

›

Open Task Manager (Ctrl+Shift+Esc) and check the Performance tab. Look for CPU, RAM, or Disk at 90–100% usage.

In Task Manager → Startup tab, disable unnecessary startup programs. High-impact items are the biggest offenders.

Run cleanmgr (Disk Cleanup) and clean up Windows Update files. Also check for junk in %temp% folder.

Check for malware: run a full scan with Windows Defender or Malwarebytes Free.

Check drive health: run chkdsk C: /f and check SMART status. A failing HDD causes extreme slowness — consider upgrading to an SSD.

Check RAM: if below 8GB for modern Windows 11, upgrading RAM is the single best performance improvement.

🌐 No Internet Connection

›

Check if other devices on the same network have internet. If yes, the issue is isolated to this device. If no, the router/modem or ISP is the problem.

Run the Windows network troubleshooter: Settings → System → Troubleshoot → Other troubleshooters → Internet Connections.

Open Command Prompt as Admin and run: ipconfig /flushdns, netsh int ip reset, netsh winsock reset, then restart.

Check that the correct DNS servers are set. Try Google (8.8.8.8 / 8.8.4.4) or Cloudflare (1.1.1.1 / 1.0.0.1).

Disable VPN or proxy. Check that no malware has altered the hosts file at C:\Windows\System32\drivers\etc\hosts.

Update or reinstall network adapter drivers. Check Device Manager for yellow exclamation marks on network devices.

🔵 Blue Screen of Death (BSOD)

›

Note the error code (e.g., IRQL_NOT_LESS_OR_EQUAL, MEMORY_MANAGEMENT). Search it for specific guidance.

Check Event Viewer: Windows Logs → System. Look for Critical errors around the time of the crash.

Run Memory Diagnostic: type mdsched in Run dialog. Schedule a test on next reboot to check for RAM faults.

Run sfc /scannow and DISM /Online /Cleanup-Image /RestoreHealth as Administrator to repair system files.

Check if a recent driver update caused the issue. Roll back the driver in Device Manager or use System Restore.

Check temperatures with HWiNFO64 or SpeedFan. Overheating CPU/GPU causes BSODs. Clean dust from vents and heatsinks.

🔒 Forgotten Windows Password

›

If using a Microsoft account, reset at account.microsoft.com using a phone number or alternate email.

For local accounts: boot to Windows Recovery (hold Shift + Restart). Go to Troubleshoot → Advanced → Startup Repair.

If you have another admin account: run net user [username] [newpassword] in an elevated Command Prompt.

Enable the hidden Administrator account from WinRE command prompt: net user administrator /active:yes, then reset your password from within Windows.

As a last resort, use a bootable tool like Hiren's BootCD PE or Offline NT Password & Registry Editor.

🖨️ Printer Not Working

›

Restart the Print Spooler service: open Services (services.msc), find "Print Spooler," and click Restart.

Clear the print queue: stop Print Spooler, delete all files in C:\Windows\System32\spool\PRINTERS, then restart the service.

Check that the printer is set as Default Printer and is Online (not showing as paused or offline).

Remove and reinstall the printer. Download the latest drivers directly from the manufacturer's website.

For network printers, verify the IP address hasn't changed. Set a static IP on the printer or create a static DHCP reservation on the router.

♻️ PC Won't Boot / Stuck on Logo

›

Hard reset: hold power button 10 seconds, unplug power, remove battery (laptops), wait 30 seconds, then power back on.

Boot into Safe Mode: interrupt startup 3 times to trigger WinRE, then Troubleshoot → Advanced → Startup Settings → Enable Safe Mode.

Run Startup Repair: WinRE → Troubleshoot → Advanced Options → Startup Repair.

In WinRE command prompt: bootrec /fixmbr, bootrec /fixboot, bootrec /rebuildbcd.

Check if a recent Windows Update caused the issue. Use System Restore from WinRE to roll back.

Test RAM by removing one stick at a time. Test storage with a bootable diagnostic tool (e.g., Memtest86, SeaTools).

🧠 CPU Reference

Generation	Intel	AMD	Node
2024 Latest	Core Ultra 200 (Arrow Lake)	Ryzen 9000 (Zen 5)	3nm/4nm
2023	Core Ultra 100 (Meteor Lake)	Ryzen 7000 (Zen 4)	7nm/10nm
2022	13th Gen (Raptor Lake)	Ryzen 6000 (Zen 3+)	10nm/6nm
2021	12th Gen (Alder Lake)	Ryzen 5000 (Zen 3)	10nm/7nm
2020	11th Gen (Tiger Lake)	Ryzen 4000 (Zen 2)	10nm/7nm

💾 RAM & Storage Types

Type	Speed	Notes
`DDR4`	2133–4800 MT/s	Most common 2016–2023
`DDR5`	4800–8000+ MT/s	Current gen, 2x bandwidth
`LPDDR5X`	8533 MT/s	Mobile/ultrabook
`SATA SSD`	~550 MB/s	Budget upgrade from HDD
`NVMe Gen 3`	3,500 MB/s	Common high-perf
`NVMe Gen 4`	7,000 MB/s	Current standard
`NVMe Gen 5`	14,000 MB/s	Latest high-end

🔌 Connector & Cable Guide

Connector	Max Speed	Use Case
`USB 2.0`	480 Mbps	Keyboards, mice
`USB 3.2 Gen 1`	5 Gbps	Drives, hubs
`USB 3.2 Gen 2`	10 Gbps	Fast drives
`USB4 / TB3`	40 Gbps	Docks, eGPU
`Thunderbolt 4`	40 Gbps	Pro peripherals
`HDMI 2.1`	48 Gbps	4K/8K display
`DisplayPort 2.1`	80 Gbps	High refresh displays
`PCIe 4.0 x16`	32 GB/s	GPU slot
`PCIe 5.0 x16`	64 GB/s	Latest GPUs

🌡️ Safe Temperature Ranges

Component	Idle	Load	Max
CPU (Desktop)	30–45°C	65–80°C	95°C
CPU (Laptop)	35–50°C	75–90°C	100°C
GPU	30–45°C	65–85°C	90°C
NVMe SSD	30–45°C	55–70°C	80°C
HDD	25–35°C	40–50°C	60°C
Motherboard	25–40°C	40–60°C	75°C
RAM	30–40°C	40–55°C	70°C

🛡️ Security Hardening Checklist

🔐 Password Strength Guide

Type a password above to analyze it...

Best Practices:

✓ Minimum 16 characters for critical accounts

✓ Mix uppercase, lowercase, numbers, symbols

✓ Use a passphrase: Coffee!Rainy5Tuesday

✓ Never reuse passwords across sites

✓ Use a password manager (Bitwarden, 1Password)

🦠 Malware Types Reference

Type	Behavior	Risk
`Ransomware`	Encrypts files, demands payment	Critical
`Trojan`	Disguised malware, remote access	High
`Rootkit`	Hides itself, kernel-level	High
`Keylogger`	Records keystrokes / passwords	High
`Spyware`	Monitors activity, exfil data	Medium
`Adware`	Injects ads, browser hijack	Medium
`Worm`	Self-replicates across networks	High
`Botnet`	Remote-controlled zombie PC	Medium
`PUP`	Unwanted bundled software	Low

🔍 Windows Security Commands

# Quick malware scan (PS)

Start-MpScan -ScanType QuickScan

# Check Defender status

Get-MpComputerStatus

# List active connections

netstat -b # Shows app per connection

# Audit policy settings

auditpol /get /category:*

# Check AutoRun entries

reg query HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

reg query HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

# List open shares

net share

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