The top appears to be dead or nearly so. There are a couple of healthy sprouts near the base, which suggests that the problem might be in the stem. This probably is a grafted tree which means that if the sprouts grow from below the graft, they will not grow to be the cherry variety you bought. If this is so, then I don't think there is anything here to save. :-(

Are there any symptoms you can see on the trunk? Any physical damage, boring, or diseased areas (cankers)? As this tree is fairly young, it is possible that the problem had something to do with the way it was planted. To find out you will have to dig up the tree and see how deep the roots are and what their condition is. This might be a good idea because if the problem is planting related, you don't want to make the same mistake again.

If you have any additional photos -- trunk or roots -- please post those as well.