My old ECS k7s5a athlon 1000+ combo seems to have, finally, bit the dust.

The fan went and the cpu was running at 90C, yes C, but what do I know? Anyway, now I try to power on and the DVD beeps, the power lights on, but no post .... is my mb dead, or the cpu, or both?

If your pc is beeping then you've most likely fried the CPU... once the CPU fan fails... you your motherboard is suppose to shut your system down but with such a old system I don't think there was that option... so it's time to get a new system

Good boards those. Mine is still running 7 years after purchase.

Any beeps at all?

have you removed the CPU and inspected it for scorch marks at all?

You should be able to see a visible black spot on the underside of the CPU directly under the die.

Probably processor is fried. You can try checking your processor on a different mb

Check Your Power supply.

Ye I would put the proc in another box and see if its broken; if it is the mobo still might be blown though so try use another processor to test that before you buy anything.