Dell Studio 1558 startup Problem

My antivirus deleted some files from system 32 of my windows7 dell studio 1558 after that i restarted my laptop but after the start up it turned blank and i tried ctrl+alt+del but after dell logo it just turned blank i tried to repair the window but not picking up the windows cd and also not responding to the f8 key and If I leave it blank it turns off automatically after 2 3 mins, anybody have solution please guide me. thanks