Hello

i suggest you use "CCleaner"
this previous thread contains more information
http://www.syschat.com/pc-cleaner-software-6671.html

CCleaner is smart enough to detect the old "temp" files that your computer no longer needs, and it will delete them for you.

you can also check right now with your Recycle Bin. Empty the contents of the recycle bin and it should give you more free hard drive space.