I understand that your system keeps rebooting every 10-15 minutes and you believe it may be related to the AMT.
In regards to your question, the AMT user is admin and password is admin if they where not set before.
At this point, please enter BIOS thru maintenance mode ( moving the BIOS jumper from pins 1-2 to 2-3) and clear all passwords, then load the defaults with F9 and then press F10 to save and exit.
If the problem continues you can disscard that is related to the AMT and start looking for hardware problems.
Please note that it is normal that the AMT LED is blinking when it is not configured.
No, my system does not reset every 10-15 minutes.
I'll try to explain.
When my system is powe off after 10-15 minutes it power automatically on for 5 seconds then power automatically off (it stays on for 5 seconds).. This is repeated every 10-15 minutes ...
I hope I explained and excuse me if I don't speak English very well.