I had this problem in January when I redid my pc. I couldn't install anything off optical drives after a clean windows install. But it wasn't on a dell computer(ASUS motherboard), I built mine. But anyway to what I remembered that did the trick. In the BIOS, look for an onboard IDE Operate Mode - see if you see Enhanced Mode/Compatible Mode . I got mine on Enhanced, but I'm using SATA HD and IDE DVD drives. The real thing is what that matters is what your enhanced modes support is set for(S-ATA/P-ATA/P-ATA+S-ATA). I would suggest putting this setting on S-ATA, that way you can get the most out of your Hard drives without affecting your optical drives.