HTC S620 wont start(dead)!

[mallik14]

hi everybody i have an htc s620 for almost an year and i never had problems with it! except a few weeks ago i was in the car and i left him in the car to charge up for about 3 to 4 hours! but when i came back i saw that the phone was out! so i tryed to start hem up but nothing happened. and i thought that the battery wasnt ok! so i tryed again at home but with the same result. i try a few times to connect with the pc/charger, but the charging flashes for less than a second. i thought that i was a battery problem but today i received a new battery but this wouldnt charge up. so even with the new battery i couldnt get any response even when connected with the pc or with the charger.

i really dont know what i can do. can please someone help me??????????

allready BIG thank you in advance..

mallik