Macbook turns on to gray startup screen but will not load and shuts down after about 45sec -1 min

Hi There,

My Macbook pro has been experiencing some craziness the last couple of days.

Yesterday it was sort of slow and I was experiencing the rainbow spinning wheel between all applications.

The battery was very low so I charged it and attempted to turn it on today.

Now, when I turn it on I am experiencing the gray startup screen with the spinning geat and what sounds like

the CD drive going ( I believe I have a disk in there). After less than 45 sec to 1 minute the machine just shuts off.

I have tried the safety start and a few other startup methods, but always the same result.

Any ideas or should I go strait to Apple hospital?

Thanks-