Default [Q] Random reboots of system after pressing the power button

I've been using CM10.1 for some time now without any major problems, but recently my phone fell like half a meter from a table and after that it started behaving weirdly:
1. The SIM was not recognized anymore (i just found out that the SIM card is faulty, as other phones do not recognize it aswell)
2. The phone keeps randomly rebooting(even after fullwipe and updating to CM10.2) after press the power button to either wake the phone or turn the display off.

I have literally no idea what could be the cause of the second problem, as It does not happen everytime I press it, but just randomly from time to time.

Thanks for any help in advance!

EDIT: I should probably also mention, that if I constantly wake the phone via the QWERTY keyboard and let it fall into standby automatically the reboots do not happen.