RockXP by Korben
Rock XP is a handy little tool that I use for two things. First, it shows the license key for the Windows that is installed, and second it can search your system and reveal passwords that a customer has forgotten. This has happened many times, usually with MSN and Rock-XP has made things much easier.
Note: (from the author’s website) “Small Warning: RockXP is a tool that allows you to retrieve password. To do that, RockXP uses a third part tool called Pwdump2.exe which is an opensource software (Sources are included in RockXp). This tool retrieves HASH password of Windows. Unfortunatly, some Antivirus detects this tool like a Virus, but it’s not. So if you have downloaded this software from this website, i guarantee a 100% free of virus software… So, now you are free to use this tool… Thanks to you.”

Ccleaner by Piriform LTD
Ccleaner, also known as Crap Cleaner, is great program for freeing up extra space on a hard drive. It scans your temp folders and cookies then tells you how much free space you gain by deleting them. I like to run it before doing a hard drive scan for two reasons: One, it makes the scan faster by having less files to analyze, and two, often times malware and trojans like to hide in the temp folders of Windows.

Winrar Trialware by RARLab
I used to use Winzip for for my archive compression needs in Windows, but WinRAR handles more file types. Not to mention, Winzip does the irritating “feature” of putting unnecessary junk in the taskbar! What is with all the different file compression formats anyway? WinRAR supports: RAR, ZIP, CAB, ARJ, LZH, TAR, GZ, TAR.GZ, BZ2, TAR.BZ2, ACE, UUE, JAR, ISO, 7Z, and Z.

Winsock XP fix freeware by Option Explicit
A common software problem with Windows computers is corrupted internet settings. We used to have to fix these by hand in a 15 step process, but we now can use this utilty to save time repairing messed up winsock settings in the registry. Everything is checking out but you still can’t get online? Run this program.

BootIt NG trialware by Terabyte Unlimited
As you may be able to tell from it’s name, this is a boot menu system for running multiple operating systems on your PC. However, that isn’t Boot-Its most useful function. It also includes powerful disk managment software that I use to copy, resize, and convert partitions. Very handy when you’re upgrading to a new hard drive.

Beyond Compare trialware by Scooter Software
What a great little piece of software, I’m amazed something like this didn’t come along sooner. Copying the complete contents of drives in Windows sucks. You’ll get about half way through a 40gb copy, and the windows copy feature will error out on a file. Of course Windows doesn’t copy the files in order, so you have no idea what’s missing. Beyond Compare solves that problem. Very, very handy.

The Belarc Advisor Free Personal PC Audit freeware by Belarc
This is a handy little tool for examing your system and telling you all its specifications in one page. I sometime use this to find out exactly what product keys the customer is using for his Windows and Office. It also comes in handy if you need to share your system specs with a friend, just run Belarc advisor and print it out.

XP Password blanker freeware by P. Nordahl
This is very handy utility I have used on several occasions. How the utility works is you create a boot CD, then follow the onscreen instructions to blank out the NT, 2000, XP, or Vista user passwords. The Linux-based text interface looks intimidating, but the default choices gets you through most of it. Sometimes this is a last resort but it’s saved the day for me more than once.