Went to turn on my PC this morning and have been having some problems.
Initially the PC appeared to powerup but I received no display, and the mobo was reporting code 25 on the number display (indicating it had stopped at PCI initialization). I then reset the CMOS and the PC posted and started up windows 7.
However, when windows started all the drivers seemed to had disappeared or been uninstalled (including the display drivers). Device manager was also reporting that one of my network LAN ports on my mobo wasn't working (the other one worked for a bit and then stopped). It was also reporting a problem with a PCI port (a few days previous my PCI wireless card stopped being recognised by windows....so this could also be part of the problem).
At the moment windows is starting up but keeps on trying to install a whole bunch of creative audio drivers (seems to be stuck on a loop as nothing ends up getting installed), and this is periodically interrupted by a BSOD with the error "IRQL_not_less_or_Equal" at which point it restarts.
I've run memtest86 and it reported no errors (plus the RAM is fairly new).
Anyone got any ideas on what could be the problem? My mobo is getting on a bit so i'm wondering if it's on the funeral march...
Mobo: Abit IP35 Pro
RAM: Kingston 4gb
OS: Windows 7 64bit
HD: Intel X25-M SSD 80gb
GPU: GTX 280
Breadboard with just motherboard, CPU & HSF, case speaker, and PSU. You do have a case speaker installed, right? If not, you really, really need one. If your case or motherboard didn't come with a system speaker, you can buy one here: http://www.cwc-group.com/casp.html
You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU.
Motherboard LED's mean very little. When on, all they are telling you is that the computer os plugged into a live power socket and the PSU is switched.
Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.
If no beeps:
At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.
The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.
This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.
If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card. Silence or long single beeps indicate a problem with the memory.
Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.
Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.