* CCleaner - Cleans up Windows systems. Clears temporary internet files, cookies, history etc.
* JkDefragGUI - An advanced defragging tool far superior to the built in Windows one
* DriveimageXML - Hard drive imaging tool. Allows you to get a single file out of a whole image too
* Explore2fs - Allows you to explore hard drives with Linux file systems
* Double Killer - Finds duplicate files and deletes them
* Deep Burner - CD/DVD Burning software
* 7-Zip Portable - Archive creating and extraction tool. Can handle most compression formats
* PC-Decrapifier - Cleans out the crap that comes installed on new brand name computers (Norton trials, toolbars etc.)
Information
* Process Explorer - Allows you to view system processes
* System Information - View lots of information about a system (specs, passwords, temperatures etc.)
* ProduKey - View software cdkeys and serials
* Autoruns - Autostart program viewer
* HWMonitor - View hardware information
* GPU-Z - Show video card information (chipset, bios version, shaders, memory size etc.)
* Wireless Key View - Shows saved wireless network keys
* TreeSize Free - Show how much space each folder on a system uses
* Game Key Revealer - View CDKeys and Serials for popular games
* USBDView - Allows you to list and manage USB devices (including devices that arent currently plugged in)
* TrID - Identifies file types for extension-less files
* Codec Installer - Finds and analyzes video codecs
* Unknown Devices - Tells you what a "Unknown Device" in system properties actually is
* GSpot - Video analyizer
Repair Tools
* Norton Removal Tool - Removes Symantec products
* McAfee Removal Tool - Removes McAfee products
* LSPFix - Fixes broken Winsock entries
* Dial-a-Fix - Repair Windows files and registries
Recovery
* Recuva - Recovers deleted files
* Restoration - Recovers deleted files
* Photorec - Recover deleted/damaged files from Flash memory (like digital cameras)
* DBXTract - Recover emails from damaged DBX files (like Outlook Express)
Network Tools
* Wireshark - View network packets
* Network Scanner - Scans the network for devices
* Putty - SSH/Telnet/RLogin client
* Network Stumbler - Wireless Network Scanner
Virus and Malware Removal Tools
* Clamwin Antivirus - Virus scanner/remover
* Rootkit Revealer - Detects rootkits on a system
* Combofix - Malware finder and remover
* SmitFraudFix - Malware finder and remover
* RogueFix - Malware finder and remover
* Hijack This! - Malware remover
* SUPERAntiSpyware - Malware scanner and remover
* Malwarebytes - Malware scanner and remover
Misc
* Mozilla Firefox - Web browser
* JavaRa - Find and remove old Java versions
* Monitor Tester - Test monitors from problems
* Dead Pixel Tester - Finds and fixes dead pixels on LCDs
* ChkFlsh - Check flash drives for errors or test their real size (as fake ones appear on eBay)
* Double Driver - Driver backup tool
* SumatraPDF - Lightweight PDF viewer
* Revo Uninstaller - Advanced application uninstaller
Tweaks
* TweakUI - Windows XP tweaking tool
* VistaTweaker - Vista tweaking tool
Scripts
* Quickly Make a System Restore Point - Makes restore point
* Reset Network - Releases/Renews IP and flushes DNS
* Clear Printer Spooler - Clears stuck print jobs from spooler
* Stop Automatic Updates - Stops "Windows has installed updates, restart now" dialog temporarily
* Start Automatic Updates - Switches it back on