Reformatting

Ok well I dont know exactly where to put this so I just figured just put it here. Ok so simple question with a short story. So I want to start fresh on my hard drive but I dont have my OS disks so i cant completely erase them and restart completely new so I thought I would just reformat them. If i go to my C drive and right click on it and press reformat, what all gets deleted and does anything stay like all my important files needed to run my computer?

Anyone?

If you format C: everything on it will disappear and you will need to reinstall Windows from the DVD.

You won't be able to format C:\ if you try this inside of Windows.

You should try using system restore in your situation.