Is it just time for a new one?

[k_woood]

I've had my S II Skyrocket for close to two years, and the past few days it's randomly been shutting off by itself and vibrating three or four times before it shuts off completely. Today it did this three times, and this past time it never stopped vibrating, so I took the battery out thinking it would stop and I could turn it back on again, but when I put the battery back in, it just started buzzing. The Samsung logo will pop up every so often, then it just goes blank again and buzzes. I'm not really sure what to do with it. :c