madrat

hey there chaps Have a begger of a prob got a comp now this is the first vista os i have delt with here that had a malicis ad on it so have removed that and computer booted normaly so i then cleaned the registry and again it booted normaly then i did a reg defrag and the comp just keeped going to the first screen on where you chose setup or recovery so i did the dignostic and every thing says 100% so i did the boot recovery and all good but the last came up with osnotinstualled no too me that looks like it has unistalled vista but how and why some help would be most excellint