Laptop fan repeatedly spins up and then immediately stops

[astrochase]

This has just literally started happening on my laptop. I heard the unusual fan behavior and noticed the CPU temp was creeping up.

The fan starts and stops in fits. It does seem to be able to spin for about half a second, but then immediately stops again. This repeats every few seconds. What could be causing this?

 

[astrochase]

I apparently can't edit my original message. However, turning it off for a minute had no impact, but leaving it off for 15 minutes did and now the fan spins again properly, although I'm guessing it may recur.