8rda+ hangs during post sometimes

I bought this board and upgraded the bios, the bios filename is 8rda3a17.bin. Anyway, no problems, have a conservative overclock with a little extra voltage to the CPU and Ram...
However, recently, I turn on the computer and it hangs during post, before detecting the drives. Reset once or twice solves the problem.
Before this gets serious, any ideas? Power supply not giving a good signal? Not much stress on the power supply, really, an "old" Radeon 7500 and a single small HD (gotta fix that...)
This is not a disk boot problem, it hasn't got there yet. The last line I get is "nforce 2 ultra 400 support" (or "fsb 400 support" or similar).
My CPU regularly runs 42C with my fans turned down slow, but has been as high as 49 when I was playing games and forgot to turn the fans up. (The noise and lack of a fast video card is why I don't push it further, which it certainly can do!) How high should I allow the CPU to get (as shown by MBM)? I may finally get some Ceramique to help, too.

For what it is worth, I had the same problem with my 8RDA3i, and it went away for good when I disabled the pc health status during post.

Maybe this helps for you too.

Is it possible your fans are too slow for the pc health in post to detect? Try turning the fans up a tad and see if it ever does it again. I am not sure what RPM's the bios is looking for, but it may think there is no cpu fan if it is turning slowly.

Yeah, I just turned them down and this started happening, now that you mention it. Why would that effect it in such a way? Actually, my CPU fan is about 2600 rpm, but sometimes MBM shows it as zero! (This is NOT the case, I can hear it, it is just slow!) I thought it was a glitch in MBM, but if it is a glitch in the electronics not being able to measure accurately at that slow of a speed.... I thought a big fan turning slow was a better idea, quieter AND can be turned up faster when I need it.

Yep, sounds like the bios is preventing startup because of the fan speed. Fortunately, you can disable the fan speed check in pc health in the BIOS, but I wouldn't really recommend it. Just try turning the fan up a little at a time until the problem goes away.