Try a hard reset.... Search the forums here for the exact key sequence... I think there are two resets one to get it back on and the other will erase all of your data during the reset. If it really is dead REI has a 100% satisfaction policy I bet they would work with you. My wife's Garmin 205 literally flipped it's lid (the entire top of the watch popped off) a month after we bought it and REI replaced it with no issues.

Here is one of the resets:

http://www.runningahead.com/forums/post/8d10a2f7d0874eb49dfd99038636eac0#focus

This one includes the the one that erases everything (so they say):

http://www.runningahead.com/forums/post/2e7757dd86ef4ed49532ec6ab11d1a05#focus

ya my garmin is slowly going down hill. Like on long runs of 12 miles or more it seems to stop the stop watch, and then i dont get accurate times or distance. very disappointing when when you have just ran 10 and a solid pace.

 Is  the garmin set on workouts. If not do a master reset. A master reset will remove all data so save it in your log firsr.

I had the same problem with my 205--my unit a little older, actually. The first time I called the customer service rep and I thought it might just be that the thing wasn't staying on the cradle, so we tried putting a rubber band around it to charge, but I should've known that wasn't it because the thing did say "Charge Complete," in retrospect. When I called back the next day saying "Thanks for nuttin'" the new guy felt so bad that they sent me a new unit--no charge!--though I would gladly have spent the $79 for it to be fixed.

Call; they'll make sure you get it set right. The hardest part is the 10-14 day wait for it to get back.