Possibly a heating issue??

IS the supplemental cpu supply voltage line connected to the mb? (Older ATX PS varriants will not have it, the P4 compatible units, atx12v, will have an additional 4 pin connector, and nearly all NF3/4 boards will also require this input to be connected, supplies the cpu with more current. In my Athlons case, it will not eveen POST without it))

Also, did heat sink come with pre-existing grey colored thermal compound? Was strip of tape removed from bottom of heatsink? Is heatsink fan connected to mb, as many mb's might refuse to run without some sort of RPMs registering on this line; must be connected to "cpu fan" on mb)

bad cpus are extremely rare, it is most likely, like 99.9% that the issue lies elsewhere. especially since you were able to boot. try some different memory, clear the cmos, make sure all the power connectors are hooked up and there are no standoffs in places they shouldnt be. how generic were the generic psus? it should be at least 350w for a generic psu to boot this system up, and with a p4 connector too dont forget.

this sounds like a power issue to me too

here's sommething funnny to try. not replaceing the PSU itself

the power cord

i just had this happen to another fellow on another board. we just replced the cord and eveything worked.

Hi Starfishy.
Any time I've seen people having problems installing a hsf, it's ended up causing problems.
Maybe there was something out of place, or maybe you are just not used to the amount of force required to install the units for the A64.
I know it's a pain, but I suggest you take the mobo back out, and reinstall the hsf.
Dont worry too much about the amount of force required, the heat spreader does a good job of protecting the core. Remember, if it doesn't feel right, it probably isn't.

Not bloody likely. I'm sure that goes something like "If it feels right, it's probably a sin"

I want to say power supply just because it's generic but during post and setup nothing is consuming enough power to put a load on it. The GT wouldn't even start to ramp up not in 3D mode and the other components don't draw near enough to tax it.

Perhaps try a single RAM module at a time? Maybe it's the SATA cable, I'm assuming you're using a cable that came with the mobo and those are usually crap!

Although, I did work on an old P3 system that wouldn't post because the power supply was bad. The CPU fan wouldn't come on, switched in a new power supply and it worked.