CPU overheat, causing no boot

[Shipflight]

So, some days ago I got myself a quite old PC. Its motherboard is the Asus P5VD2-MX and the processor is the Intel Duo 2. The case had this old 300W (cant really remember), but no connectors for PCI-E. So I switched out the power supply to a newer CX750M. The problem with this was that upon boot, the CPU overheats to well above 70C, immediatly, and fails boot. I do aswell have the G1 760 plugged in, and I can't get any display upon boot. I've cleared CMOS, and the PC boots up if the CPU power is not connected. Any solutions?

[GreezyJeezy]

change the thermal paste and dust it

[Moonzy]

2 minutes ago, Shipflight said:

I've cleared CMOS, and the PC boots up if the CPU power is not connected.

you mean it booted without cpu 8 pin?

[done12many2]

3 minutes ago, Moonzy said:

you mean it booted without cpu 8 pin?

That would be interesting, yet not possible.

[Moonzy]

1 minute ago, done12many2 said:

That would be interesting, yet not possible.

that would be a huge flaw in the board's circuit if thats the case lol

[Shipflight]

46 minutes ago, Moonzy said:

you mean it booted without cpu 8 pin?

The motherboard has a 4-pin. And it turned on, maybe it did boot, yet i did not have any videosignal

[Shipflight]

36 minutes ago, DEcobra11 said:

Put new thermal paste and reseat the cooler for the overheating part.

Also looking at Asus' site there're some BIOS versions where they added PCI-e cards support... so... what's your BIOS version?

Can't really check as I need the CPU to process my video signal. Would have been easier if I could gotten to the BIOS

[Crossbred]

Check fan headers, reapply thermal paste, clear out dust, and if all else fails get a newer but inexpensive cooler like a hyper 212 model.

[Shipflight]

Yes, it was the god damn stock cooler. That piece of shit didn't have enough surface coverage. I applied some more thermal compound and ensured the cooler was fastened. CPU is at the edge of overheating, yet I dont care lol. 

Thanks for the help