My computer with windows XP was built by a well known local store. It worked fine for almost two years and then motherboard and video card needed replacing under warranty. It then would sporadically quit working. It has been in/out of his shop most of 2007. He thought that virus from “watching porn” was the fault. However, that was not the case and recently he also replaced hard disk too,. Each and every time I take it back because I am getting the “reboot and select proper device” message but he plugs it in at his shop, runs it over hours, and it runs fine. I bring it home, plug it in and it gives the black screen message again. He is treating it as if I am doing something to it. My laptop works fine, an older machine works fine on same station but not the XP desktop. He has quit talking to me about it. I had paid him $200 to wipe all of the harddisk just before the time he replaced hard disk. Any suggestions?