Boot Disk Error PLEASE HELP

Hey all, I have a Compaq Presario SR1650 running Windows XP Media Center Edition that is getting a boot disk error. It is basically all stock except for a NVIDIA 8500GT video card and an additional GB of RAM. The issue started when I installed a program that would monitor the computer temps. I noticed the video card was running at a 103C. I knew that was way too hot so I shut down the computer, popped open the case and realized the fan on the video card was not working...after fooling around with it and not able to get it working..I decided to go back to my onboard video, so i took out the video card (which was the only thing I touched) and turned the computer on, and it would not boot up at all...The fans would come on, and run at a high rate constantly, but nothing showed up on the screen. I did some research and had to take out some battery from the motherboard and wait...still nothing. After having the power unplugged for about 15 minutes I decided to try again and got the disk boot error I turned the computer off and back on, and it came back to giving me nothing on my screen. It did this constantly and then I waited again and got the disk boot error message again. I went into the BIOS and realized my HDD group priority says it's not installed, not sure if that is the issue. It seems to go between nothing showing up on the screen at all with the fans running high or a disk boot error screen. This whole issue started over a graphics card that was overheating, but it could have been that way for weeks, I'm not sure..

Any tips or suggestions would greatly be appreciated

 

Tried reinstalling the NVIDIA card, booting into XP, removing the card (drivers) through Device Manager, powering off, removing the card, rebooting and reinstalling on board video device with Device Manager?

 

I am not able to get pass the boot disk error msg..

 

I'm guessing you've done all the basics? Checking connections, clear CMOS etc.

 

I got in contact with a good friend's dad who is a computer tech that lives in South Dakota. He advised me to go to a website and download Hiren's Boot Cd 9.8. After downloading the disc and burning it and getting to the screen to run diagnostic tools, the screen froze, restarted and now I can't even boot from a cd. Going back into the bios I have noticed now my cd boot priority group is messing. So now I have nothing bootable that my computer is recognizing. Yep I have done all basic troubleshooting. Cleared CMOS...checked all cables 100 times...totally stumped on this

 

Hmmm ... have you got another computer your can test HW components on??