Right out of the box, Windows is just a so-so operating system. It doesn't really reach its potential until you've cracked it, hacked it, and otherwise bent it to your will.
Whether you want to speed up XP, customize Vista's Aero interface, manage your disk partitions, or do quick-and-dirty photo editing, its mandatory to have a quick look at the Windows.
For more information please do refer to the article from pcworld. Hope it would be useful:
PC World - Windows Tips for Everyone