Arduino defect? Not programmable, stk500_getsync() attempt 10 of 10: not in sync

Hey Guys,

I bought a new Arduino. My first porgramm was easily transferred and everything is okay. Now i wanted to change my program, but it stucks at the "upload". After a long time it come following error:

avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
Probleme beim Hochladen auf die Platine. Hilfestellung dazu unter http://www.arduino.cc/en/Guide/Troubleshooting#upload .
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x03

Also, pin 13 doesnt blink anymore (if i press reset). If i press Reset, pin 13 and ON-LED sine brighter than before (very weak). Also the On-Board LDO gets very hot (with USB??).
I think its defect?

#EDIT: Can't be a IDE/Driver/Cable Problem. My second Arduino works 100%. Should be clear, that this Arduino is death... But why?!