Not sure why others are having problems, hopefully an "expert member" will chime in soon. Let me just repeat what I did and if you did something different that may be the source of the problem. I downloaded and ran Tony's installer. I then ran Update Extra (NOT NBI) and then restarted. Shaved about 50 seconds off my boot time (now it takes a minute to boot instead of a minute and 50 seconds). I've had no problems. I checked my "About this mac" extensions and it shows HDA 1.7.9 is my audio driver kext now instead of SL 10.6.3's HDA 1.8.4 audio driver. However, my S/L/Extensions folder, 1.8.4 is still there, but is now in a folder. My advice is to try to boot in safe mode, kill Tony's kext with the terminal command for killing and deleting kexts, re-run NBI and keep your fingers crossed this works. If not, hopefully and expert will way in soon. I AM NOT AN EXPERT. Again, keep us posted!