Please can someone tell me what could possibly be wrong with my laptop?

My computer was working great that is until last night. Last night it didn't want to shut down, it stayed on the microsoft page with the words 'shutting down' for a long while, I finally had to take the battery out to get it shut down. What could cause this? Was it just one of those things или this there a еще series problem?

I'll tell Ты that I have windows vista with no desire to switch to 7 или 8 because, I like vista and my computer I just want to know why it didn't want to shut down last night please and thank you.

(Props for anyone and everyone who can give me a straight answer.)