Help I have C*****UP my 7210

What have I done?
Old Nokia 7210 was ok ~To lazy to take the back off, looking for number I entered #06# on key pad [mistake!!] ~ started to emit regular low level beep noise ~ keyboard now inactive ~ switch on lights up then dims after about 8secs.... requires press on start button to light up ... no keys active .. another press to turn off ?
With sim ~ intro screen then to profile menu ... keys inactive .... dimming etc. as without sim ???
helpful suggestions please.
As you guessed I am new to all this! :-?
thanks ~ D