I downloaded a program tat said it could help me clean my regisrty because my computer had crashed. I accidentally deleted important files like access to any .exe file or something like that. Now I cant even open the My COmputer Icon or anything else. I made my problem even worse, Can someone tell me what to do?

How do I access the restore? I got this pc of )@#% from my father in law and he got it from his company, i dont have any software or backup disks, so what can I do?