To Thong Ispector, yes my fan has 3 wires and i will get some thermal grease
and give it a go.The only thing that is bothering me is the voltage applied when i power on is in milli seconds rather than seconds, is that enough for it to heat up? i will get back to you after i have used the thermal grease wether it's successfull or not.thanx again Eamonn.
ps do i just put some grease on the copper plate covering the chip or smear the whole CPU?

I usually just put a thin coating on the copper contact spread thin and the same on the heat sink, then a tiny drop right in the middle as I put the two together.

Double check before doing this that you didnt bend any pins on the cpu when you installed it.. And that it is turned the correct way... notch to notch etc...

Since it only stays on for a millisecond I tend to think the motherboard is not seeing your cpu fan spin up.

Sorry I am running out of options here...

You are sure the system never got power without the heatsink in place...

To Thong Ispector, put the grese on like you said, guess what? no difference ! i even stripped it down completely using the manual, instruction by instruction, put it all back, added just a smoll drop of grease, again the same. You say in last post about powering on with heatsink off, tried that, same, but the fans deffinetly rotated for less time ? i always wear an earthing strap while working, the only time the CPU was handled unprotected was when the guy in the shop swapped the CPU from 1 MB to another, could there be a problem there?
thanx again Eamonn.

I said... You sure the CPU NEVER got power...
Powering up your CPU even the shortest time without a heatsink can damage it.
This whole problem seems heat/fan related...
A heatsink that is off center or at an angle or not locking down correctly. A heatsink/fan that has a bad speed sensor that isnt sending info back to the motherboard.. Something like that. I would try a different heatsink/fan and if that does not work take it back to the place where you bought it.

I would think that the guy that sold it to you would have powered it up just to show you it worked.

To Thong Ispector, Ive mailed the guy who built my PC 3 times before i got an answer, when i did all he said was check the PSU voltages after switch on, wich i did, powered up, fan span, shut down, as usual. I then removed the ATX power connecter and measured the voltage on all 20 pins, pin4 @ 3V (soft power), pin19 @ 5V (for soft logic), all other pins are 0V. Ive now mailed him 3 times again with these results, they mean nothing to me except that for some reason all other voltage Potentials were at 0V, still waiting for a reply. This is the guy when i was having probs, crashing, internet cut off,BIOS errors, low CMOS battery, sys clock kept ressetting to May 2003 etc, mailed me and said my PC is not doing anything it shouldn't !!!! .The CMOS battery was fine by the way. As he hand built it for cheap Ive got no legal recourse here. But how do you test the ATK 20 pin plug unless the whole system is powered up ?
thanx again Eamonn.

I dont know how to test one of those other than what you have done.
One of the few good things about being a packrat is all of the extra power supplies and assorted parts I have around.
You might check to see if there is a computer user group in your area.
You can find some free help and access to free pieces and parts.

Your old board spowered up right? it didnt have a display but the cpu fan spun up and lights came on etc?