Hi, Bev.

Bad sectors on your hard drive, bad install disc, and hardware can be the cause.

I would first make sure there was actual contiguous space on the hard drive. Download Smart Defrag for free and use deep optimize setting from the drop down box. Windows defragmentor is useless. After defragmenting, the resulting graphs will give you a visual aid to determine how much contiguous space is available. You may have to make room.

Have fun.