I have a MDG 3150DL desktop computer with Pentium D procesor, Radeon X1550, and 250GB Hard Drive with Windows Vista Home.
It stopped booting a while ago. I recently got it to boot after reconnecting everything, removing the video card and modem, and took out what I thought was bad ram. After I got it to boot and load Vista, it turns out I forgot the password...and I hadn't made any recovery disks(I was pretty dumb) so, I installed Windows XP using an installation CD doing a complete format (cause I've heard of conflicts between the two OS). But when I tried to start it later, it won't boot again! It doesn't make the beeping sounds anymore when I take out the ram. I pretty sure it's not the power supply cause it was JUST working.
Ok I tried it but it still won't boot. The first time I tried to boot it it ran for about 5 seconds then shut off on it's own and wouldn't turn on, but the motherboard light was on. Then, I flipped the power supply switch off then on again, and when I booted it, it continued to run without booting, same as before.