I use a program called privacy guardian off download.com

Whilst it erases your internet tracks e.g. cookies, address bar, it also cleans out all the unecessary rubbish too like recent doc history and all that.

Also go to control panel and uninstall everything thats shit and you dont use.

Also setup files for downloads, get rid of them after install and winzip files (those that have been unzipped keep and delete the zip file)