Hello,
I'd first try and change the battery. Most
Suunto batteries are only good for 1 to 2 years, depending on usage. The battery is easy to change out, just make sure to follow the instructions (don't use a screww driver!, use a nickle!) You can find the battery kit here:
http://www.suuntowatches.com/Suunto-...attery-Kit.pro
This being said - you should have gotten a low battery warning on the watch?
If not, you may want to put a call into tech support at
Suunto and see what they have to say: 1-800-543-9124
As far as I know - you will lose your data upon battery change. The way to avoid this, of course, would be to sync first - which I realize is not an option.