SOMETIMES no graphics card output! Strange problem.

[hiddepolen]

Hi everyone!

I have a strange problem, I haven't been able to solve, even with quite some knowledge of videocards, and computers.
I have an nVidia 250 GTS, purchased a year ago (all new, no second-hand). Everything worked very well, until about a month ago. Sometimes, when I power on my computer, there is just NO output to my monitor. If this happens, the videocard does get power, the fan does start spinning for a while, but my screen stays idle. Also, if this happens, it is always when I power on my computer, NEVER while it is on.
I have the correct drivers installed, both Windows 7 and Linux (Ubuntu 10.10) don't want to show...
My onboard VGA worked perfectly, everything as well, just sometimes the videocard. Sometimes it suddenly works again, that's the strange part. I don't know what goes wrong, so I can't repair it...
For the last two days, there has been no output at all, I'm all on my onboard VGA now.

Specs:
ACER MCP73PV
Processor: Intel Core 2 Quad Q6600 (Kenfield) @ 2.40 GHz
Bios: American megatrends R01-B2
Memory: DDR2, Single channel, size = 4096 MBytes
Graphics (onboard, because I cant see a thing when I plug it into my GeForce 250): NVidia GeForce 7100, 256 MBytes, 600 MHz
PSU: 550W, recently bought.
Windows 7 and Ubuntu dual boot

Anyone has any solutions?

Cheers!
Hidde

[mjdodd]

I assume you have checked all the connections including removing the video card and then replacing it fully pushed down with its holding screw tight. Just one pin not connecting with the motherboard slot can give this symptom.
A dodgy power supply (ie not constant) to the video board may also be suspect;
Beyond that there may be a sticky memory location on the video board. thereby refusing to accept a memory input on startup, but OK when warm?. hope this helps
M

[hiddepolen]

Thanks a lot for all the info!

I'll try this all, although I have tried cleaning it, and tightening the screw. I'll post my progress...