My Benq Siemens El71 Turns On Says Benq Siemens...

Question

Hi everyone my silver benq siemens el71 was the best phone ever i got it as a present by my brother it worked fine it was a very loud and fantastic phone,but 1 day i went swimming so i had to turn it off and put it in my locker so when i get home i turn it on and it says benq siemens on a white screen then goes beep and turns off then goes black screen.please someone help me out to what the problem could be.thank you very much!!!