samsung s2 not responding anything

when i turn on my mobile it jst shows the first screen where the "samsung galaxy s2 GT19100". after that it stays on the same screen. i have tried by turning it on n off still its same. taking out battery for 10 mins n tried again the same. my mobile had never met any kind of accident not even a small falls. it all started this morning when i was charging it. my battery % is 20%. thought the battery was down n charged for more than 30 mins bt no sign of charging too