What's wrong with it?
Remember that general wear and tear isn't covered by a warranty agreement.
Optical drive failure/iSight failure etc etc is.
However if it's issues of crashing or freezing, erase and install the OS. If you've never done that before and your machine is approaching 3 years of age, it makes sense that you're experiencing fluctuations.
I wouldn't' recommend restoring from a TimeMachine backup or an Archive and install. You may just be transplanting the problem.
It's a chance for a new beginning!
Perhaps an excuse to upgrade to SL???
🙂