Computer

I have a 95 Firebird T/A and the air conditioning compressor was not running. After I took it to get it looked at they said the compressor would not turn because the computer had to be reset. My question is how do you do this so I know next time? They fixed it quick but I would like to be able to do this on my own. Thanks for the help in advance.

Disconnect the negative battery cable for 5-10 minutes.