https://theretroweb.com/motherboards/s/asus-p5pe-vm: 'supports some Conroe Core2Duo CPUs with iGPU disabled' , if the igpu is enabled you have to use fsb800.

Thanks for your reply, if you mean the onboard GPU, I already have an AGP card connected to the board and monitor. Is there anything I should do further, for that?

Then it should have worked. I have a lga775 with 865 Gigabyte board and a lga775 ECS board with via PT880 Pro which don't support core2duo and they act the same when i put one (no post). What revision is your board ?

Could that be due to the circled bottom of the CPU on the picture? It's Rev. 1.00G.

That looks like a 'surface scratch', i've seen worse and the cpu was still working, but you can test it on a newer lga775 board just to be sure. I have the https://www.gigabyte.com/Motherboard/GA-8I865 … -G-RH-rev-20#ov (rev.2) and does not support c2d, but as you see the later revs support it, so because you have the rev.1 of that board i'm thinking is the same in your case.

It seems I will need to test it with an another motherboard.. Well, if I could find some.
Regarding the motherboard revision, the asus page says "ALL" I don't really think that's the main case.. 😒
(And since BIOS version 0604)