Okay This guide ? :
"If boot stops right before reaching the installer, or graphics aren't working right, delete video kexts:
ATI = AMDRadeon* and ATI*
Intel = AppleIntelHD*, AppleIntelSNB* and AppleIntelFramebuffer*
nVidia = GeForce* and NVDA*
You can also move kexts booting in single user mode (press space bar in Clover or type -s in Chameleon)"
With this code ? :
fsck -fy
mount -uw /
mkdir /kext_backup
cd /System/Library/Extensions
mv AppleIntelHD* AppleIntelSNB* AppleIntelFramebuffer* AMDRadeon* ATI* GeForce* NVDA* /kext_backup
rm ../Caches/com.apple.kext.caches/Startup/kernelcache
reboot
I'm so sorry but i'm a novice & i'm french so it's so hard to understand guide ..