black screen. Advanced HELP! needed

Hi, I restarted my pc and now i get no display at all with no cursor. Cannot get into safe mode, bious or start from xp install disk. (no display). Monitor works fine tested on other pc.
I was using s-video before last shutdown and wonder if display is somehow switched, dont think so because i have tried to restart and view desktop on my tv, not there.
Recently new install (2 weeks) due to floppy diskette seek failure/error loading operating system problem. upgraded from xp home to pro. (shouldnt be a problem). Running fine till i installed catalyst control centre and used it, i think this was also the case when i started to have problems leading to last reformat, but prob just a coincidence ?
I have a dell dimension 9150 and it has error reporting lights on the front that are displaying 1,2,3 along with 2 beeps at startup. This is what the error report means. (just lights)

An other failure has occurred.

This pattern also displays during System Setup and may not indicate a problem.


* Ensure that the cables are properly connected to the system board from the hard drive, CD drive, and DVD drive.
* Check the computer message that appears on your monitor screen.
* If the problem persists, contact Dell.
link to dell diag lights
http://66.102.9.132/search?q=cache:...ard&cd=3&hl=en&ct=clnk&gl=uk&client=firefox-a

Restarting and hitting f2 will start and no error code displays but restart and hitting f12,f8, xp disk or no keys all get same error code.At no time does the power light on my monitor change from orange to green.
I thought it might be my graph card Radeon x600 (dont think i have an onboard one, no other monitor connections) but there is an error code for card failure and most other major problems, which i am not getting? I also never got any signs it was failing.
Things i have done so far.
Removed, cleaned pins and reinstalled ram and graph card. Removed battery from motherboard (10 mins). Cleaned all dust, needed it. Removed heatsink and re-applied new thermal paste, reset bious with pin jumper, removed and reseated all wires.
If there is any way to reformat, i would. any help would be greatly appreciated. Pulling ones hair out.

 

I would start by checking your grafix card in another pc . Then disconnecting all optical drives ,extra hard drives , memory card readers etc and leave just one stick of ram and try that first.A faulty piece of hardware could cause the problem you describe. Try changing your ide cables as well

 

In addition to stable-cottage's suggestions,

When you power on your pc, do your fans turn, do any peripheral lights come on, do you get any indication that you are getting power?

If you are getting fans and lights initially, does your pc go through its normal startup patterns, minus the video; i.e., do you hear the whirring sounds speeding up and slowing down, beeps and things that you normally hear as your OS loads, or is it just a flatline?

 

Thank you stable & scooby. Will try and check card tomo. Fans work hd makes a noise but not so much speeding up and slowing down, two beeps and there is a green light on the m board and power light on front is normal stable green.

 

OK good deal, your best bet is to do as stable-cottage suggested and check your vid card to rule it out, then go from there. My experience with this problem in the past has been either a dead mobo or a dead psu, but you've just got to go at it one piece at a time. Did you say you already checked the ide/sata cable your hdd uses? I'd think you'd at least get a bios screen if that were the culprit but it can't hurt to be thorough.