How and when to reset your Mac’s PRAM and SMC

How and when to reset your Mac’s PRAM and SMC -

There are times when your Mac will just start misbehaving. Video settings getting reset, fans start running at full speed, keyboard lights don’t come on when they should.  This is most likely to happen following a hardware upgrade, extended power outage or even a major software upgrade (like Lion). In those cases, sometimes you need to reset your Mac’s parameter random access memory (PRAM) or system management controller (SMC) to get things running smoothly again.

(Via TheAppleBlog.)