PC won't boot, only fans are running

[MrBigwell]

Hello everyone,

I need your expertise regarding an issue I have with my Gateway FX541XG desktop computer. Since two days ago I am trying to figure out why my computer doesn't boot. When I start my computer, the power button indicator, optical drive indicator and hard drive indicator light up for a few seconds and after, turned off. No beeping sound, no signal on the monitor. The only hardware that are running are the fans, nothing else. These are the steps I have made to try to resolve the issue:

I unplugged the power cord and I pressed the power button for 30 seconds....No change.
I tried to identify if one of the RAM sticks doesn't work connecting only one stick on every slot having the other three disconnected....No change.
I replaced the CMOS battery....No change.

I am running out of ideas of what to do next...I am thinking at the PSU, but the PSU fan are running fine.
Any new idea of what else to test will be highly appreciated.

Thank you in advance for a possible reply.

[DaveLembke]

I'd swap out the PSU with a known good power supply. You can have a power supply run with fans spinning and a voltage rail is low causing failed boot.

[MrBigwell]

Thank you for your reply DaveLembke

I followed your advice and I tested my PSU (Delta Electronics, model DPS-700FB-1 E), paperclip test and seems that is defective (PSU fan didn't start). I bought a new compatible PSU (unfortunately didn't find the original one), EVGA BQ750watt and replaced the defective one...After I installed it and connected all the cables I pushed the start button and is doing the same thing, nothing's changed.
I am thinking now at the motherboard but I find hard to believe that two important components (PSU and motherboard) broke at the same time.
Any idea of what should be my next step regarding checking or testing?

Thank you

[DaveLembke]

Could be CPU FAN Tach not detected and then it performs a shutdown. If you physically see the CPU FAN moving then this is not the cause.

Clear the CMOS ( BIOS ) and then try to boot. * Also check the voltage on the coin cell it should be 3 volts. If its weaker than 2.94 volts it could cause POST issues. Usually they are slightly greater than 3 volts like 3.06 VDC when battery is healthy.

Other thing to try is remove all the RAM and install just a single stick of RAM and boot. If same, then shut off, and install a different RAM stick from the 4 into it and see if you find a stick of RAM as the cause. If it boots on a single stick of RAM then one of the RAM sticks is bad or one of the memory bank slots is damaged or the memory controller has an issue.

Looking up the specs it looks like it came with a Geforce 8800GT video card. If it had integrated video try to get it to boot without the video card but on integrated VGA video.

Last test is disconnect all hard drives and optical drives, remove all addon cards that are not necessary for boot and see if  you can get it to boot at minimal hardware. If it boots then and behaves then work your way back adding the devices back with the computer off until you find the device that is causing this issue.

If none of the above works then its then its likely main board failure.

[patio]

Nicely done Dave...very thorough advice.

[MrBigwell]

Thank you Dave for your suggestions. I did all the tests you advised, except the video card because I don't have one...Is just an integrated graphic processor on motherboard.
Unfortunately didn't make any difference. The part that is making me thinking that might be a defective motherboard is the absence of any kind of beeps. Even with the RAM sticks totally removed there isn't any error beeps.
I started to look for the original MOBO (NVIDIA nForce 680i LT SLI)...At a first search didn't find any...If I can't find the original MOBO, can you suggest a compatible one?

Thank you once again for help

[patio]

Would you please tell me that you install the drivers properly in your windows?

At this point it is NOT a driver issue...re-read the Post above...