Enable integrated graphics after dedicated graphics fail

Removing the discrete graphics card should enable the integrated graphics.

I tried this with no luck, so should I still replace the graphics card or does the problem lie elsewhere? Also when I tried this both my hard drive and optical drive were removed. Would that impact my cause of failure or should the moniter still display something on the screen without the HDD?

PS The fans run at full speed all of the time.

I would try clearing the CMOS to set all BIOS settings to their default options..

Optical and hard disk drives are not required for the system to pass the POST (i.e. Power On Self Test) process.

Which video port on the Back I/O panel do you have the monitor connected to?

What is the make and model of the monitor?

Yes, reset the BIOS to its default settings. You can do this by removing the battery on the motherboard(shouldn't be too hard to spot) for a minute then putting it back in.

My monitor is connected to a VGA port on the motherboard and I have tried two monitors, a LCD and a CRT. Both monitors work on my other PCs, so it’s not a monitor problem. I also tried resetting the BIOS by removing the battery on the motherboard for at least 5 minutes, still no luck. My PC had this very same problem in April 2010 and it was under warranty at the time so the folks at best buy fixed it and said it was caused by a graphics card failure. What is new this time is that the OS would crash more frequently all the time with a blue screen event titled “Bad Pool Header”. It got so bad that I had to reinstall the OS every day to use it, until it stopped working altogether. I read somewhere online that the “bad pool header” event was caused by malfunctioning RAM, is that true? Should I replace all 8GB of my RAM?  

Thanks, I'll try that

ok I removed all but one stick of ram and hooked the tower back up to the monitor. All of a sudden the fans slow down and the boot screen appears, so with a bit of trial and error I will be able to pinpoint the bad ram stick. Thank you all for your help.  

Best answer selected by bDavidrk.