Default cm10.1 reboots every time the screen times out

i run cm10.1 (4.2.2)on my lg p990 aka optimus 2x. i had no problems until i tried installing the kowalski kernel.i installed it and it wouldn't work..so,i restored my backup which i did before installing the kowalski kernel,and now the problem is too serious...my phone reboots as soon as the screen timeout runs out...even if i try to install some other rom,it still flashes the current version just with data wiped...someone help me..please