Computer won't POST -- continuous reboot -- no beeps

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spagbowl

45 posts

Geek

#95950 17-Jan-2012 13:22

Hi Geeks,

Any thoughts and/or suggestions would be greatly appreciated. I have stripped the system down to breadboard config to eliminate any electrical shorts but with no luck... No beeps, nada.

System Specs:
Motherboard: Asus M2A-VM
CPU: Athlon II 445
PSU: XFX Pro550W
RAM (x2): 2GB Kingston HyperX PC6400
GPU: Gigabyte Nvidia 280GTX

Backup and known working PSU: Generic 400W

Here are my symptoms:

On power-up the cpu, psu and gpu fans start. The power LED on the motherboard is alight. After about 3-4 seconds on, the power goes off. After another 3-4 seconds the system comes back on by itself and this loop continues until I switch off the psu or pull the plug. At no point do I get any POST beeps or video output.

The problem began when I switched out an 8800GT for the 280GTX. The above symptoms became apparent so I purchased the more powerful psu. Using the 8800GT again or no gpu at all produces the same problem.

Motherboard busted..?

k1w33d

138 posts

Master Geek

#570934 19-Jan-2012 18:36

Not sure if you have reset bios/cmos but you can try the following.

Unplug your power cord, Unplug everything from the mobo execept the mobo power cables, 1 stick of ram, graphics card (try running it with no graphics card using the integrated graphics.), cpu fan(no usb devices, headers drives or anything), remove the cmos battery, move the bios reset jumper to pins 2+3 for 10 seconds then move the jumper back to pins 1+2, put the battery back in. plug the power cord in and power up it should beep and u get keybaord error, or no hard drive error. If you get this then start plugging in the keyboard + drives one at a time and rebooting each time, keep doing it and if you run into the same problem, reset the bios again. Hope you get it working, let me know how you get on.

Virgil

Dangerous Chocolate
206 posts

Master Geek

ID Verified

Lifetime subscriber

#570946 19-Jan-2012 18:53

I wouldn't write off the motherboard just yet, but it does sound like something has become unplugged or loose.

Chances are removing and re-inserting the RAM sticks and the CPU will make it spring back into life. Also check and reseat any other add-in cards.

Good luck!

spagbowl

45 posts

Geek

#570954 19-Jan-2012 19:08

I've tried all of the above but to no avail. Thank you for the ideas. Anything else?

heretohelp

360 posts

Ultimate Geek

#581555 14-Feb-2012 21:08

could try a psu

Hu? did i do that?
16Mb (EDO RAM), K6-II processor, 2Mb of onboard graphics. 32k dial up modem. 12 speed CD ROM. 5¼-inch floppy drive. 500Mb HDD.

xxXStylusXxx

42 posts

Geek

#586130 24-Feb-2012 10:22

It sounds like there is a lack of power to the motherboard, have u got the plug in to the top left of the cpu on the motherboard?

stevenz

2802 posts

Uber Geek

#586171 24-Feb-2012 11:45

I've seen this sympton a few times. It's usually a motherboard issue caused by incorrect configuration (such as when overclocking the CPU more than it can cope with), or lack of power (particularly if you've got a fairly serious graphics card).

K1w33d has pretty much the routine I'd use. Basically, if it powers up and stays going with just the CPU and a single stick of RAM (no drives, no graphics) then the motherboard is probably ok.

You might have a dead CPU but you'd have to try pretty hard to kill one so I'd doubt it, but depending on the motherboard, it could produce this outcome. Try reseating it just in case if you haven't already. (Might've whacked the heatsink during GPU installation, hard but not impossible - I've seen heatsink mounting hooks pulled out of the board before, they're a b*stard to fix too).

I can't see an onboard speaker so presumably it's one of the ones that plug in to the header block?

@KnightNZ

spagbowl

45 posts

Geek

#586720 25-Feb-2012 17:26

Thank you all for the advice. I reinstalled Windows and now it is working fine. I guess that I changed too many components at once for Windows to be stable.