Beep Beep Beep...

Alright, I normally leave my computer running all the time, but my fan's been rattleing some, and it keeps me up when I try to sleep, so I shut it down. I should say I didn't mess with anything on it, I just pressed the power button and laid back down. This morning, I press the power button, and it just starts beeping, sorta like there was somethings stuck on the keyboard. I cut it off and back on, same thing. I open the case, give the processor fan a little twirl, and it works the next time I cut it on...

I should say the processor fan has about given out on me. One day I walked out of my room and returned to the smell of something burning. I ran to my comp to find my fan was spinning(or being read) at 0RPMs! I quickly shut it down, oil the fan, and use it again. It's worked fine untill today. I guess the oil settled in it :/

Well, any ideas what would cause those beeps? I know nothing was on the keyboard because it was pushed under my desk. My MB has a feature where it will shut down if the processor fan ever stops(apparently I forgot to enable that ) but no alarm...