A common cause of slow computer performance is a hard drive that is close to reaching it’s storage capacity. As a good rule of thumb, your drive should always have a minimum free space of 10GB or 10%, whichever is smaller; more if you burn CDs or DVDs, which usually requires temporary free space equal to the size of the material you’re burning.

A program that can help you manage your hard drive stoarge is WinDirStat.  Check  it out in the Download category