Probably you know this..
Just thought to emphasize it..
If yur system hangs donot press the reset button...
There is an option to restart immediately..
Go to task manager ctrl+alt+del under processes choose explorer.exe and press end process...
Your desktop icons, status bar etc, will disappear..
do not panic..
under files in task manager click new tast and type "explorer"..
Done... your system is back again in its perfect shape..