My iPod power button won't respond!

I have a iPod 2g pre-owned and I had it for about 7 months and it was working perfectly and for some reason the power/sleep button won't work.it's not jammed, it's not broken it won't respond. A couple of times it turns off and on by itself but after that it won't work. I can get it to turn on once in a while. I tried blowing the inside and I tried tapping it with my finger but still no respond. Please help