I have a three year old Hewlett Packard Pavilion Media Center m8300f PC. I decided to upgrade the power supply to a Zumax X3 Series ZU-650W and install a MSI N9500GT MDIG/D2. I installed the card no problem, but I was having difficulty with getting the computer to recognize the CD ROM drive. The factory power supply does not have enough SATA power connectors to power both hard drives and the CD ROM drive, so HP had put a converter on the CD drive to convert from SATA to peripheral. I remembered this and, without thinking, attempted to plug the peripheral connector into the converter that was attached to the CD drive, all while the computer was turned on. I mis-aligned the peripheral connectors and connected one of the pins to the wrong female connector. The computer instantly turned off. The power button on the front of the case didn't work and the I/O switch on the power supply didn't work, but I recalled that disconnecting the power cable from the power supply would reset it in the event of a surge. I did so and it powered back on, automatically checked the discs for faults and continued booting up. Everything was fine, even my CD drive.
I shut the computer down and let it sit for a few hours because I had to do something elsewhere. When I came back, the computer would not boot. The BIOS do not post and there is no image displayed on my monitor. I have tried both the new video card and the on-board video and both do not work. I systematically disconnected every disc drive and card. I have switched back to the old power supply and tried the same method of diagnostics. I tried resetting the BIOS and the CMOS using the jumper switches on the motherboard. I have taken off all four sticks of RAM and tried each of them in each of the RAM slots. The only time that the motherboard BIOS beeps a code, or beeps at all, is when no RAM is installed. I've attempted to press F10 to reach the BIOS but to no avail. All the fans work, so the motherboard gets power. I checked the tops of the capacitors and they are not leaking nor swollen. Occasionally during testing the computer would start up when I plugged in the power cord or flipped the I/O switch, without me pressing the power button on the front of the case.
I hope that helps you help me. Thanks again.
Edited by Trind, 18 May 2010 - 12:59 AM.