I have a computer here that just got a new MB and CPU and now it wont turn off after you tell XP to shut down. Everything goes blank but the hard drive light stays lit. If you hit reset it will come back up and Windows says it wasnt shut down properly. Its an AMD Sempron and MSI motherboard. All the other hardware was left over from the old MB/CPU. I didnt do the install but now Im the one trying to fix it! I replaced the IDE cable so far and that didnt help.