Restarting The Computer?

I was just wondering why do people have to reset the computer? Someone please reply cause I was told I have a Computer problem and didnt know if it needs to restart or a new one.

unhook the negative battery terminal for a minute or so

according to vfaq...that is stil not resetting the ecu....you have to do it from the plugs under your drivers side..

Yes, but why Do people need to restart the ECU?

to reset trouble codes and lights on your dash that are on