PSU: 520W
FANS: 5x 80mm
MOB: Asus K8N 32/64 (Socket 754)
CPU: Athlon 32/64 xp3000+ (Socket 754)
RAM: Legend DDR400, 2x 512MB Dimms (one single, one double)
IDE HDD1: Western Digital 7200rpm 120Gb ATA-133
IDE HDD2: Western Digital 7200rpm 160Gb ATA-133
IDE Removable HDD Rack: + Western Digital 7200rpm 250Gb ATA-100
AGP Video: 6800GS 256Mb
PCI Sound: Soundblaster Audigy
PCI Network: DSE 10/100/1000mbps card

I'm using Windows XP Pro SP1 build, with dx 9.1c and nvidia drivers 68.x (the latest drivers out have caused 100% cpu usage when playing video files, but the older versions work fine)



>>> This setup has been working *absolutely* fine for the past 18 months. I have never had the following occur. <<<


 

NO DISPLAY, SOLID AMBER 'HDD' LIGHT ON STARTUP, NO BEEPS.

I un-installed a game called "Medieval Lords: Build, Attack, Defend" and like many apps it advised I needed to perform a restart. I did this immediately. No display showing (monitor on stand-by mode) with a solid amber 'hdd' light (the light that usually denotes hdd activity) - no beeps but I decided to start by checking my video card.

- Swapped AGP video card with budget 4mb PCI one. No change.
- Checked motherboard for power. Green LED (always been on in the past) still on. Fans are spinning.)
- Cleared CMOS by moving jumper to pin 3, then back again. No change.
- Uplugged ALL IDE devices. Should display BIOS version and give option to enter bios. Still no display, HDD light still solid.
- Removed both Memory DIMM modules, tried one at a time in all 3 RAM slots, before putting both back in. No change.
- Removed PCI cards. (IDE devices still un-plugged) -- Basically minimal power now. No change.
- Removed CPU, cleaned the fan and re-seated it. No change.
- Disconnected ALL power cables and fan plugs from the motherboard, plugged in the power plugs for motherboard. No change.
- Added fan plugs back to motherboard. No change.


At this point I feel it could be a naffed motherboard, or a damaged CPU. Is there anything further I can do to rule out any other bits of hardware as being the problem? My next plan was to test my cpu on another socket 754 motherboard, but I don't know anyone who has one, (my mates use PCI-E 9xx socket motherboards and I need a 754 with AGP slot) -- I would like to try another cpu on my motherboard too but... there is a risk that if my motherboard is faulty it might damage any other cpus I try to add.

Is there anything more to be said for this problem and a solution? I'm out of ideas.