PC won't start-no display

This is another PC than in my specs.
HP SR1750NX
HP S2331 monitor 1920X1080, 23" LCD
Win 7 Ult 32 X86, came with XP MCE
AthlonX2 4400 2.GHz (added)
4X 512MB Corsair value RAM (2X 512MB added)
ATI HD 4670 GFX card (added)

A few weeks ago our power went out but the PC gracefully shut down because I have a UPS attached. When power returned the monitor said "Check video cable." The HDD light would come on, blink a bit then go out or stay on solid. I had to hold the PWR button down to power off and re-start, which got everything back to normal after a try or two.

To day another power outage and this PC won't start at all. Upon powering on again there is no display and the HDD light stays on solid, or will blink a bit and go off. This motherboard has no speaker so I'm not getting a beep code.


Steps so far:
Changed video cables and source from VGA>DVI>VGA>DVI
Reseated RAM, GFX card, and tried a different SATA header.
Pulled the plug from the PSU

After pulling the plug it won't shout down by holding the PWR button in, it will slow ( I hear the fans slow down) and immediately tries to restart.
With no display to see what's going on, I'm lost.

Have you tried powerdown including really turing off external power ( switch psu off). On again and boot in safe mode?

Assume you also tried another screen?

+ if I'm not mistaken, your mobo also has integrated graphics. You tried that too?

Do i read right that this desktop did something after pulling a psu plug???

The PSU has no switch, but yes I have pulled the plug when the switch won't shut it down. The mobo does have integrated GFX, it won't work either. I can't boot into anything, the HDD lights are either on steady on on then stays off, with no display to see what is happening.
Haven't tried another monitor yet, that is next.
This first happened when the power went out due to a storm a few weeks ago, but then I could get it up and running by powering off with the switch and cold starting once or twice.

I guess the second monitor test + testing THIS monitor on your main system is the next step. Since you have two systems, that is easy to do.

If the monitor and its cable prove to be in order... then there is not much more to try but pressing <del> or whatever you used to try to open in BIOS or F8 to open in Safe mode and see if it makes a diff. As a last resort.. a cd boot with a restore disk or something, just to see if a CD boot is different from a HDD boot...

Yes the monitor is fine on my other PC

Were you able to try bios by pressing DEL or F8?

Yes I could boot to BIOS after I removed the GFX card and the machine boots with it out and using the on board GFX. The monitor tested fine on the other PC, which made me say hmmmm.
It seems the Gigabyte GFX card is toast or conflicts after running for several months. any with it out all seems good so far, just no Aero glas effects and resolution is ver limited.

Thanks for your efforts. :)

My pleasure... but, before you really toast the card... I'd try to test it in another system or... in another slot on your mobo...

I was thinking of trying the card on my system, kinda sick of looking at computer innards right now.