PC powers on/off 10 times, then boots

[flexta]

Hi, never really had to post on a PC support forum before so bear with me and any info I may have omitted to post, please feel free to ask for!

About 4 days ago, I switched on my PC: the case, CPU and PSU fans started as usual and the CD drive lit up but the blue light that surrounds the power button (and the red CPU indicator) failed to illuminate. The monitor remained blank, no beep and the system failed to boot. The fans continued to whir until I switched off the unit using the on/off switch located on the back.

It's a pre-built, 2 1/2 year old tower which had been running fine until now. I suspected the PCI-e attached graphics card (Nvidia GeForce 9500GT) could be the problem, so opened up the case and removed and reinserted the card on the off-chance it had somehow come loose. That seemed to do the trick - after this, the PC booted as normal.

But later that day, having shut down my PC earlier, the exact same thing happened again (fans but no lights, no boot). This time, reinserting the video card did nothing.

My motherboard has integrated graphics, so I removed the card and connected a VGA cable to that instead. Now, a different problem occurs. The computer powers on with all fans running, the blue power light illuminated (but not the red CPU indicator) for around 3 seconds before shutting itself off (nothing appears on the monitor and it doesn't boot). It proceeds to do this at least 10 times before booting and running as normal.

This happens on every power on. Is it that the PC is still searching for the disconnected graphics card or something more serious related to the PSU or motherboard? Was the graphics card the problem after all?

Specs:
Biostar G31-M7-TE
Intel Core2Quad Q8200 @ 2.33GHz
Intel G33/G31 Express Chipset Family (Integrated Graphics)
(Previously - Nvidia GeForce 9500GT PCI-e)
4GB DDR2 RAM
Windows 7 Professional x64 SP1

Thanks

[Tyree]

Brand & Model of the PSU?

[flexta]

Originally Posted by Tyree

Brand & Model of the PSU?

Evo Labs Model: 600U (600W).

[Tyree]

That would be the prime suspect.
SeaSonic-XFX-Corsair (not the CX or GS Series) are top quality PSU's.

[flexta]

Thanks, would you recommend taking it to a repair shop to be sure it is a PSU issue before ordering a new one? Also, how straight forward are they to replace?

[Tyree]

That would be your decision but replacing that unit with a good quality one is only a win/win deal.
To replace- make diagrams, take pics, or both of all the PSU connections.
Disconnect the PSU power cord and push the case Power button a few times to discharge the PSU, remove all the PSU connections, remove the four screws retaining the PSU to the case and remove the PSU.
Installation is the reverse order of removal.

[flexta]

Originally Posted by Tyree

That would be your decision but replacing that unit with a good quality one is only a win/win deal.

I'm unsure as to why it's acting one way with the graphics card in and another with it removed but I get your point - looks as though I've been fortunate to get this long out of it! Thanks also for the advice.

After a quick look around, would something like this be up to the job?

[Amd_Man]

That's a good power supply you linked.

[Tyree]

The TX Series Corsair are top quality SeaSonic built units and the one you linked to would be fine for your hardware.