Originally Posted by 55/Rad
Clean the chain as mentioned. But also check the derailler adjustments - your cables can certainly stretch over a year to the point where you might hear some rubbing.
+1. Unless you've really been abusing the bike, your chain and cassette are both fine. If you haven't adjusted your derailleur in the past year, it is almost certainly out of adjustment. If you put install a new chain or other components and the problem is your derailleur, you'll still have the noise. No sense in throwing parts at a problem until you know it's necessary.
Like Machka says, 2,000 miles is nothing.