I'm posting this as an aid to anyone who runs into a similar problem;
maybe I can save someone a little pain.

I have an Enlight EN-7230 case
(http://us.enlightcorp.com/products/p...case&serial=61),
and a few weeks ago I started noticing a burning smell in the room
after the computer had been on a while. I opened the case, sure that
the cooling fan on the CPU was dead, but it was fine. I ran SpeedFan
(http://www.almico.com/speedfan.php) to be sure, and found the CPU and
case temperatures to be well within limits.

More checking revealed the problem to be with the power supply, which
in this case was an EN-8254942. The fan wasn't spinning, which had
made the power supply overheat. I pulled the power supply out and
removed the fan to look it over. It turned out the fan bearing (which
in this case is a sleeve bearing rather than a roller bearing) had
seized. I removed the impeller, which can be done just by pushing on
it, and lubricated it with a few drops of 3-in-1 oil (I've read that
you should use a heavier oil, but this worked for me). Then I
reassembled the fan and reinstalled the power supply.

I switched the computer back on, and with a little encouragement the
fan started spinning again. The computer is usable for the time
being, but to be safe I have ordered a replacement power supply (a
Sparkle ATX-300GT) -- a worthwhile insurance policy at $28 including
postage.

One other item of note. The EN-7230 has a small fan at the bottom of
the case near the front, and while looking things over I noticed that
one of the screws that holds my hard drive in place had blocked that
fan from spinning, too. That's a design problem, since one would
expect a fan included with the case to have enough clearance to
accommodate mounting screws. I moved the screw to another hole, and
that fan is now spinning as well.

Moral of the story: if you have an Enlight case and you smell
something burning, you might have a look at the power supply fan.