it doesn't work at all.........it freezes.......uuuuhhhhhhhhhhhhhhh..........does it actually working though ????

Can anyone help please, I'm an iPhone 3GS new user, I had unlocked my iPhone before and update to iOS4. Then suddenly it was locked again.......I tried on iTunes to restore my previous version of 3.1.3..the iPhone restarted and but from then I can only make an emergency call. Does anybody has an idea what do I need to do next..........please help out of this and I would appreciate if you also can show me how to unlock my iPhone 3GS......Thank you very much