Problem with Asus GeForce 8800GTS?

Hi,

I currently have a problem which prevents my computer from starting up, and I suspect the reason might be a broken graphics card, but I'm not quite sure about it and would like to hear your opinion on what needs to be repaired.

My hardware: Abit IP35-E, Intel Q6600, Asus GeForce 8800GTS, A-Data 4GT DDR2 800MHz, Antec Sonata III Silent ATX (500W), Noctua NH-U12. OS: Windows XP Pro 32-bit

The current problem: When I switch the computer on, I only get the Abit motherboard startup screen (Press TAB to go to post screen, Press DEL to enter setup), but it gets stuck there and pressing TAB or DEL (using a PS2 keyboard) does not help. I have even tried to reset the motherboard by removing its battery for 10 minutes, but it did not help either.

Why I think the graphic card could be the reason: I have had some problems with the graphics and the startup for a half a year now. Quite often when I restarted the computer after a break of several hours, the startup didn't succeed the first time but got stuck in a black screen where the Microsoft XP logo appeared. I also have the feeling that it stayed longer than usual on the Abit motherboard screen and used less time to show the following DOS-like startup texts that precede the XP startup screen. So I had to switch the computer off and restart, and the second start was almost always successful. But even when the startup was successful, the Microsoft XP logo appeared by transforming from dark to bright gradually and very slowly (in steps of half a second).

I also had some other graphics issues: inside Windows, the menu texts suddenly started to look somewhat unclear. The menu texts started to look better only when I went to Display Properties/Appearance/Effects, unchecked the option "transition effect for menus and tooltips" and changed the "method to smooth edges of screen fonts" option to ClearType. Also, when playing GTA IV, the far-away objects had quite hazy edges.

Why graphic card might not be the reason: As far as I've understood right, the motherboard should be able to display its own setup screen even if the graphics card is broken.

I'd be very grateful for your help!