Dell restore and recovery problem

Hi guys, I am trying to restore my friend's Dell Inspiron computer. It came preinstalled with Windows 8. The system is so corrupted that the only way to make it work again is to do a clean install. It has loads of malware, viruses, pop ups. I can't even install or uninstall a program. I've tried using the dell restore and recovery program to no aval, doesn't even launch, same with...