Not all computers can be restored to factory settings. F8 is for accessing System Restore to go back a few days, not Factory Restore--that's Control + F11. Factory Restore is a fairly recent utility. You need to mention your model computer, operating system and how old the computer is or just follow the directions for PC restore HERE.

I have a Inspiron 1525, Purchased last March so it's a year and 4 months old, Operating System Vista Home Basic.

There's another way to restore the factory image using the Vista disk instead - not quite as easy, but easier than a clean install..   See instructions here:

http://support.dell.com/support/topics/global.aspx/support/dsn/en/document?docid=298A2E89689E13C2E040A68F5B280AA4&c=us&l=en&s=gen#2

But it will only work if the original  factory image is still intact on the D: partiion.    If it was damaged or removed, you'll have to reinstall from scratch.

"F8 is for accessing System Restore to go back a few days, not Factory Restore--that's Control + F11."

Unfortunately, Mary is incorrect. F8 is the key to access the factory restore on Vista systems and Control+F11 is the key to access the factory restore on XP systems.