Uh-oh... my MBP keeps going to sleep!

[fairy lights]

I have a 2 GHz intel MBP with 1GB of ram, which is a little battered to say the least, and I've had it now for a long while, as I purchased it soon after the initial MBP release date back in 2006. Recently it keeps randomly going to sleep while I'm using it, and it has full battery or is plugged in, so it doesn't really make any sense to me! It wakes up fine but sometimes it just keeps going back to sleep.
Does anyone have any ideas about what it could be? My mac has been running slower than usual of late, but it only has about 10GB of free disk space now, so I thought that that was kinda normal.
I'm a bit concerned because I don't want my precious MBP to die on me!
Thanks!

 

[daneoni]

High thermals will usually force a laptop to sleep to keep it from frying itself. Also 10GB free space is a bit on the low side so maybe try doing some cleanup. You might also want to check out Onyx or Cocktail which are utilities that can 'spruce' your system.

Another thing to try is an SMC/PRAM reset. If those dont work then make an appointment with a Genius (i assume you have AppleCare)