William Sommerwerck wrote:

By the way, check the CPU cooler occasionally. Mine
hadn't been cleaned since I bought the computer over
eight years ago, and you cannot believe how clogged
with shmutz the heat sink was.

I clean them moderately regularly. Plus I don't operate
in a very dusty environment.

Nor do I. This wasn't dust -- it was more like gobs of sub-microscopic
carbon particles.

Never seen that. On the CPU cooler itself you mean ?

Grham