Symbian tricks of hard reset of s60v1v2v3v5 and s60^3

hi this is a very useful trick of Symbian.when your Symbian phone works very slowly or hangs,attacked by a virus,or its software gets damaged then this is best way to come out.
instructions
-your phone battery should be fully charged.
-2 persons are required for proper functioning.
for non-touch phones
-switch off your phone.
-press power on button,green(call) button,3 key and * together.
-phone will start and ask for country,date,time etc.
that's done!!!

for touch screen phones
-switch off your phone.
-press power on button,green(call) key,red(call end) key,camera key together.
-phone will start and ask for country,date,time etc.
that's done!!!

note:- you should backup your important data and contacts before resetting.