resetting the computer

I have a 1997 Quest, that had a bad o2 sensor. I replaced the bad one and cannot get the computer to reset, I tried by disconnecting the the battery and using the hand held scanner, any suggestions??

Thank You,
Tom

There are 2 ways for clearing codes without a scanner.
1) disconnect neg battery cable for 24 hours.
2) with key "on" disconnect diagnostic connector in engine compartment
and jumper pins 3 and 6,after 2 seconds reconnect connector and
turn key "off".