I was a victim of the same and figured out the solution on Saturday and have been using my system for 3 days now without any issue. Who should try this hack? If any one is true for you its worth trying.
- You have recently upgraded your RAM from 2GB to 4GB or above.
- Your MAC Book Pro or what ever mac machine came with Leopard and you just installed snow leopard from somewhere.
- You tried formatting and various stuffs still Firefox and Safari hands and various programs becomes "Not responding" and you need to kill them.
sudo systemsetup -setkernelbootarchitecture x86_64 It will ask for your administrator password. Provide it and restart your machine. Voila! Facts: Open activity monitor and see all the default apps has started as 64Bit now.