This might be a bit lengthy so I will apologize in advance.
While playing a game the other night my video froze, I couldn't Ctl Alt Del to fix the problem so I had to turn the computer completely off to try to get it to reset. Now after turning the comp back on, I get a screen that detects my video card and the amount of memory on it, then it goes to a black screen with a blinking curser in the top left corner. I have tried to boot from a startup disk, and tried to go into bios as soon as the power is turned on, and it still goes straight to the blinking curser. I am running Win 98, 768 megs ram, GeForce 5200 Ultra Video card. Any idea what might cause this to happen? Thanks

Turn your PC off and disconnect the power cord. open up the case and find the CMOS battery on the motherboard. It'll most likely be a round Lithium cell in a clip holder. Remove the battery.

After waiting for a while to allow any residual charge to drain (longer is better, but several minutes could be enough) replace the power and try starting up again.

It sounds like the 'hard' power off might have corrupted the CMOS settings, and removing/replacing the battery should reset BIOS to defaults again for you.

Open Bios setting, In Bios there is one opion called as Primary Display or Init Display in Integrated Pheripherial option, In that Select AGP. Save the setting and exit also try changing the CMOS Battery, I guess the Battery is also week in your Mother Board