Lots of things can fill up your hard drive,here is a few examples,
1 If you d/l movies and you decide later to delete them from your libary unless you choose delete from library and computer they all will stil be there,
2 the most common thing that can take up alot of gigs on your hdd is system restore points ,I have seen this take up to 150g,windows will make shadow copies of your system , go here and read how to delete restore points,except the most recent one,this will gain alot of space f ya,
http://windows.microsoft.com/en-US/w...-restore-point