|This is a drastic move. If you decide to go down this path make sure you have all the install CDs for all of the software on your computer including Windows and the Drivers for your computer.|
Personally I would simply go to Programs and Features under your control panel and begin removing programs you don't use.
Either way, I suggest you do a system backup to an external drive before you start. Should do this anyways just in case your hard drive fails.