Are you saying that it's never been opened? Most wines are not really meant to be aged and should be drunk within a year or two. Some wines benefit from a little aging and can be cellared, usually for about five years. And some can be cellared for much longer.
Of course, leaving it on your countertop doesn't really qualify as cellaring.
And as mad jew, the wine expert, says: Opened wines should be drunk within a few days.