They are known for the batteries going after 2/3 years, but it is usually the street pilots, not this model,
Your only option is to have the battery swapped out, before you change the battery, try to let it totally drain of power first, then see how it is, when charged again,
or factory restore it,
hold your finger on the lower right corner of the screen, while turning it on, the keep pressing the lower corner, till the message clear all data appears, this will erase all data, you will have to re-register it and re-update it after this,
This may cure it for you,
if not let the battery drain, try again, if no success then, it will need the battery replacing inside it, Garmin will do this for you
If you have any question's please ask.
Hope this helps