the computer geek swiss knife...

LiberKey is an useful collectionf of utils running directly from your usb stick or whatever else, requiring no installation. Moreover it comes with a controller application allowing too run all the included software, checking periodical updates etc...Give it a try :)

an useful system admin tool

just in case you forgot your windows admin password, this is one among the thousands of recovery tools, but quick and little (just a 3mb bootable image)

http://pogostick.net/~pnh/ntpasswd/