System Restore.
 

How do I do it? The thing where you restore it all to look like you just bought comp.

System Restore just loads information from the a checkpoint. So unless you have a checkpoint from the very day you bought it, doubtful, then you can't get it to that point. You can reformat which will make it like new, if that's what you're looking for.

But, if you wan't to SR, go to:

Start > All Programs > Accessories > System Utilities > System Restore

That is what I meant, how do you reformat?

Ask samichna.