The easiest way to start Regedit is to hit the Window key on your keyboard, type regedit, and then hit Enter. (You can also do this by clicking on the Start button as well.)
Before you make any changes it's probably smart to back up the key or subkey you're planning on tinkering with. Once...
aero snap
background
backup registry
buttonset
desktoplivepreview
dword values
extendeduihovertime
ie8 title
logon screen
minwidth
registry hacks
system tweaks
taskbar previews
taskbar tweaks
user interface
user personalization
value data
windows 7
windows customization
windows explorer