PC powers on with post beep but display stays black
Hi, this is my first time posting on this site and I need help. I have built everyone in the house's computer and if something goes wrong I can usually figure it otilout and fix the problem. Not this time, I'm about to fix it with a hammer.
My system- ASUS P4SD-LA Stingray mobo with a pentium4 CPU, 2Gb RAM, Maxtor 40Gb SATA HD, ATI 9800XT video card,M-audio Audiophile 24/96 sound card and 500w PSU running Windows XP.
So, everything was running fine until last week. I normally don't shut my system all the way off, I just put it in hibernate but for some reason I turned it all of the way off. The next morning when I went to turn it on it wouldn't boot into XP and gave me a missing file error message ( I forget which one). I ended up having to do a system repair with the install disk starting from XP SP1. When I got to the SP3 disk my CD-ROM drive crapped out on me and I had to swap it for a different one, got repair install finished and when I rebooted it seemed to be OK except I couldn't connect to my network at all. The next time I booted it up I had no display on my monitor, all of the system fans were on, I could hear the HD, but no screen.
I'll try to make this long story shorter, this is what I've tried so far (not necessarily in this order)-
removed all cards, cables, etc. and cleaned the contacts, put them back in.
It ran fine for 1 day, then just a black screen again.
Reset CPU heat sink with new thermal paste
reset northbridge heatsink with new themal paste and tape.
tried the monitor on different system (it works)
tried 1 stick of ram at a time
reset bios with the jumper, removed battery
tested the PSU and tried a different one
made sure nothing was shorting on the case.
Nothing worked. All I get at this point is running fans and a post beep. I have a black screen on the monitor, I can't even get to the post or bios screen.
I'm thinking that the northbridge chip is toast from possibly over heating. Does this sound about right? It is the only thing I can think of, but if anyone can help me figure this out I would be eternally grateful.