SYTEM HANG ON FIRST BIOS SCREEN
Your MB(motherboard) is hanging at the POST(Power on Self Test) level , which means a device connected to the MB or the MB itself has failed or is not seated properly. Your MB is fairly old so I'm assuming it was working at it stopped working at some point. To help you we need some additional info, and you need to troubleshoot in a systematic way one item at a time from the easy to fix to the more complex. You should turn off the computer between each step, don't touch anything inside with the PC power supply turned on.
1. Power off your PC (POYPC), and label (take photos and tag) and then remove all external USB cables from the motherboard, only leave a keyboard and video plugged. Then boot up again and see if anything changes... If it doesn't go to the next step
2. POYOC, ground yourself and open the case by removing screws from the back, your MB has chassis intrusion detection system so the system should beep and show an error prior to POST, if your system doesn't beep then we don't have an external speaker connected to the MB which makes it more complicated to troubleshoot. Now try to push/reseat memory DDR2 SDRAM, PCI/PCIe video card, disk cables and power cables from power supply(PS) to MB. Try booting up again.
3. POYPC. Do you have a PCI/PCIe video card? Is your video cable connected to the VGA (blue plug) or a video card? If you have a video card remove it by unscrewing the video card screw, and plug the monitor to the motherboard. Now reboot, if the system passes POST then you have a bad video card or video card component.
4. POYPC. with the PC now open label and disconnect CD drive, hard disk(s), and floppy data cable from those devices, you can use a sharpie to label each cable their device with numbers. And try booting again, and see what you get at the post level. If at this point it boots, then plug one item back at a time to see which one causes the issue.
If those steps didn't solve the problem then it might be a memory (RAM), Power Supply, CPU or MB issue. These items are more complex to troubleshoot.
RAM: You have 2 SDRAM sockets, so if you have two DDR2 DIMMS remove DIMM1(closest to the CPU), and boot up again, if you get stuck at the same spot then POYPC again and swap the DIMMS so you only have the original DIMM 2 on DIMM1 slow. Boot up again and see if that gets you passed the POST, if you do you will get a memory error saying that the memory config has changed.
Power Supply: Very unlikely that is your PS because your getting to the POST. If your MB detects any electric short at all including the power supply, then your MB won't boot up at all. So I doubt this is the case.
If you get to this point and the PC didn't boot then it's probably an issue with the CPU or MB. : If either of these 2 are the problem you should replace both the CPU, and motherboard, if you stay within your RAM and video card specifications then you won't have to replace a lot of components.
