Problem with windows

Hello,when i open my computor i get 3 messages first one is system32/system32.exe cannot load,i cannot download any antivisus programs also i have them on my computor but i cannot run them as they are exe files i cannot open anything in add remove programs either, the message also says remove it from registry but i don't know how to, and if i did what would happen,besides i don't even know how to get into the registry...please help