Black screen when boot, after install

[wayneoats]

I have a Thinkpad T60 with a core duo 1.83 ghz, 1.5 gm of ram and a ati x1300 Ok heres my deal, I installed 10.4.9 the installation went great, i boot in os x the apple logo appears, after 15 seconds a black screen apears, so i restart with my external display it boots in to osx and everything is fine, i then install the natit ati 1300 driver, repair disk permissions and restart, i get into osx and now i have qe/qi but i still am using my external display, i add my correct display info in the kext wich was 1024x768x32. I then restart the computer with just my built in display and i get the black screen, does any one know what seems to be the problem.