Ok i am not quite sure whether what i did was correct but my PB hang on me 3 times yesterday when i was retrieving files from my PC to my PB. Now when it hangs on me, i take a few steps like forcing the not responding program to quit. Since it failed to quit, i press the power button and hold it there for 3 secs and then a dialog box appear asking me to either restart, sleep, shut down etc. I click on restart but then nothing happen. So i press the power button down and hold it till it shut down. Now when it did, i press the power button again to activate the PB. Now is this ok or is there any other way that i can do if my PB hangs again in the future?