Toyota Repair: Car did not turn off when key removed, plus very loud screeching noise, toyota camry, pully

Question
My wife has a 99 Toyota camry with 107K miles.  She recently turned off the car and removed the key.  The car kept running and was making a very loud screeching noice.  She put the key back in and was able to turn it off fine.  Now we can start and stop it no problem.  However, I think there is still a problem.  Any ideas on what this could be?  It kinds sounds like a pully may be seizing, but when we restarted it, it was working fine.  Do you think it is worth taking it to the dealer proactively so the car won't strand her.

Answer
The most likely cause is that the starter is the problem, it sounds like it stayed engaged after the key is off, I've seen this happen a number of times before, the starter has developed an internal short, replace the starter before a serious problem develops like the starter engaging while driving or it shorting out completely which may take the battery and the cables out with it.