Computer keeps turning on when in Sleep

[theapplefreak]

My macbook, 3 years of age, always turns on whenever I put it into sleep mode. It gets REALLY annoying. So I close the lid, and a few seconds later, you hear the macbook turn on, then a few seconds later, it goes back to sleep mode. This happens endlessly and it gets really annoying.
I was wondering if anyone had problems like this with their computers and if there is any solution to fix this, please let me know.
Thanks

 

[I WAS AN EMPIRE]

try downloading Caffeine, I'm finding it useful. there's the link:

http://www.versiontracker.com/dyn/moreinfo/macosx/31941

 

[JD92]

I found this sort of thing can happen if you do anything with the USB ports or bluetooth. For example, if I close my Macbook then take my iPhone out of it's dock then the fans will rev up again and the Apple logo will light up, then a few seconds later it'll all go back to sleep again.