I have a really nice issue. My PC has been working perfectly for about 9 months now. Two days ago, I left home for 2 hours came back and my PC was turned off. I went to turn it on and no power at all. I checked everything. The power to the PC is fine. I had not hardware issues recently and I have not changed anything new. I have a Intel quad core processor, with a compatible gigabyte MSI motherboard. The motherboard has an p1 24 pin connector and P4 connector for the extra processor power.
I found out when I have the p1 connector in, the PC will power on, all drives, cd roms and fans are one. If I plug in the p4 connector, you have hear the PC try to turn on and the fans try to turn but then no power. This does not even happen in one second it is really quick.
Does anyone have an ideas what is this cause. To me it seems like the power supply is fine because it can supply power to the PC with the p1 connector. It is 450 watts and it has been working for nine months fine.
Do you think the motherboard or processor is OK. Could the processor notice a heating issue that quick and shut off? Also while I was out there was no power surge at home. So nothing happened to the PC.
I am having the exact same problem with my hp m9040n after trying to upgrade power supply. Did you ever get this resolved?
Does the computer turn on to the Setup screen, the screen where it says like, F10 for setup?
The solution may as said above, a Power Supply Unit decided to go. If you added new hardware, graphics card, hard drive, cd drive, unplug the new hardware piece and try starting the computer back up.
If you have a graphics card, and there is also onboard graphics, try unplugging the graphics card and then try using the onboard graphics. If it works, it should be the Power Supply Unit.
Also, I just remembered this, try unplugging, the keyboard? I think it should be in a USB port. You might have to get a PS/2 keyboard in order for it to work.
PS/2 port looks like this(where the smiley face is, it should be, ":" "P", no space, the site thinks I am trying to make a smiley -_-): s-2-ports.jpg" rel="nofollow" target="_blank">http://en.wikipedia.org/wiki/File s-2-ports.jpg