I apologize but I don't quite understand your instructions. When I boot the computer, the Apple logo appears with the rotating icon, and after a while I'm presented with "You need to restart your computer." When I boot the computer using the "-s" flag, I see a console telling me that "Package 0 didn't get an HPET"

When you say "Also check in System Profiler if the AppleIntel - kext is loaded", I don't understand how to view the System Profiler. All I have is a command prompt.

Thanks for the quick reply!