It will create a folder in your documents called "CSS" with 2 subdirs,demos and screenshots. 
Now, whenever you run the script, it will move out all demos and put it in the demos folder.
Screenshots will be renamed like this: YYYY_MM_DD_H_mm_ORIGINALNAME.
This makes sure that you don't overwrite any screenshots.
It also deletes the following folders:
downloads, DownloadLists, cache. This script has been tested on Win7 x64 / x86. I'm not sure if it'll work on XP. 