GS3 won't respond at all!! HELP??

[crysselizabethh]

I was using my Galaxy S3 by the pool today when it suddenly shut off. I pressed and held the power button, volume button, home button and any possible combination of the three but was still unable to get my phone to respond in any way whatsoever. My next step was to take the battery out and leave the phone in a dry place, given that the humidity in Los Angeles lately and the fact that it may have gotten wet may have been a possible cause as well. After about an hour I put it back in, and did receive a response- it turned on and slightly vibrated, but would just get stuck on the "Samsung" startup screen and shut off. I've left it alone for about 5 hours and just now tried to turn it back on, but I get the same response. Also I might add that when the battery is in the phone and I connect it to a charger, it does not respond at all. If anybody has any ideas as to what it may be I would be grateful for any advice you can give me, thank you.