samsung t401g phone turns on then shuts off?

[Aaron]

ok I got this phone 2 days ago and finally set it up the way I wanted it with music, contacts, backgrounds ect. I was using it all day today with no problems what so ever and I turned it off and back on and it shut off and turned back on and shut off and turned back on and so on. so I took out the battery for about an hour. I put it back in and the same thing happens. it goes to the net10 start-up screen then reboots over and over again and I cannot use it. so I took out the memory card. same thing. then I took out the sim card and it finally came on and said no sim card inserted emergency calls only. the I tried a different sim card. it said sim card rejected. so I pluged the phone into the charger with the original sim card and it said charging. then i turned it on. same thing. then I looked up some codes to reset the phone. so i had to take out the sim card so the phone would actually stay on and typed it in. it worked and i put the sim card back in. this time it sounded the start-up tone because i reset the phone the made a loud pop and shut off. and restarted. and shut off. this is really pissing me off. I just got the phone 2 days ago and barely used it for about an hour. I don't know why it is doing this. I have never had this problem before. I really doubt someone else has and I probably won't get an answer. but please help!!!!!!!