Monitor flickering, maddening!

[Vyrien]

Hiya Hexus, my stepfather's PC causes the monitor to flicker, similar to when you look at a video of a monitor through your phone camera and it looks like it's alternating between brightness levels, most obviously when dark colours are being displayed. This behaviour continues in safe mode too, he's using windows 7 64bit.

I've tried 3 monitors on the PC, 2 were old square Dell flatscreen things (flicker less obvious), one was an 18.5" LCD Packard Bell widescreen (1366 x 768, flicker extremely obvious) and all connect through VGA. None of the monitors exhibit this behaviour when connected to my PC (AMD HD 6950) or my brother's laptop (crappy intel core duo with integrated graphics).

The motherboard in his PC is an asus m5a78l-m lx3 and he is running an Athlon x2 processor with no dedicated GPU. I have tried pretty much everything I can think of (updating drivers etc) besides buying him a cheap graphics card which I am going to try tomorrow but before doing this I thought it might be worth seeing if anyone here has any suggestions.

Thanks guys.

[kalniel]

Possibly an issue with the RAMDAC on the onboard GPU, a cheap graphics card would be a good solution. Alternatively could be interference from something, so check the IO shield isn't pressing against anything it shouldn't be and so on, though a graphics card might solve this issue as well.

[Domestic_Ginger]

Change the graphics drivers back to windows standard ones maybe. It doesn't sound like the cable as I presume you used it with the laptop. You could try changing the red just to check. Is this a new problem?

[Vyrien]

Thanks guys, yeah I tried using the default drivers, also changed the cable and used the same one on the laptop/my PC. It's not a new problem but the monitor he was using before (the flicker was barely noticeable on that, another square thing, I assumed the monitor was dodgy) died so we tried other monitors and then I noticed the problem was with the PC rather than the monitor.

[Domestic_Ginger]

To find out if its broken hardware or Windows maybe try a live Linux distro to see if it happens in the bios screen. Maybe check to see if something odd is checked. The windows install disc menu may replicate the problem.

Change the refresh rate in windows. Aero enabled. Excuse the rambling. You've probably tried them all.

[Vyrien]

Okay, I bought a cheap GT 610 for his PC, fixed the problem.

Thanks for your input guys, I really appreciate it.