thanks for the reply, i have deleted the following kexts: ATI* AppleIntelHD* AppleIntelSNB* NVDA*
my system uses the ati 6850, the onboard intel graphics are NOT used. (i did try booting the usb without the 6850 which didnt work)
i booted with "-f -v GraphicsEnabler=No" like you said and this is the final screen before black screen and system restarts:
anything else i can try? thanks for the help so far
*good hack*