A few weeks ago my pc just cut out for no reason and when i tried to restart, there was no POST beep.

I stripped it down completely and reconnected everything in case the mobo was getting shorted and put back together.

After restarting there was still no POST.

I have tried using a barebones system and even tried just using a CPU and graphics card but nothing.

Ordered a replacement CPU thinking it was dead and still no POST even on barebones.

I have noticed however that the chipset fan is not working. Would that have any effect on POST? I don't want to buy a chipset fan for no reason like i did with a CPU

DFI LanParty UT NF3 ULTRA D Socket 939 Motherboard
AMD 64 3700 CPU

I take it you are getting power to the motherboard? Put a multimeter across one of the leads (+12v and + 5v)?

Any sign of LED's lighting up?

Inspect the motherboard for small cracks...

Check everything is seated properly..

Remove memory sticks one at time and replace one at time to test...

Although if you have a working PSU? and You have replaced the CPU and you are happy that the memory is working then it could be the Motherboard. You could also try clearing the CMOS (use motherboard manual for details) of removing the battery and leaving out for 10 mins or so...

Good luck :)