The computer did not give any instruction. The computers went into alternate law (i.e. "act dumb, do 100% what the pilots command") precisely because the computer had detected sensors were giving conflicting readings. It was down to the pilots to determine what was needed to be done. The correct course of action was fairly obvious. They were flying at altitude, where maximum speed and stall speed are very close to each other. That is, any significant loss of airspeed risks stalling and disaster. The correct course of action, if there's a problem with airspeed indicators, then is to ensure airspeed is preserved - i.e. descend. This is real 101 stuff when it comes to "Flying high".
The senior co-pilot, in command at the time, knew what had to be done, so did the captain (who was not on the flight deck initially). Unfortunately, despite both of them clearly ordering the junior co-pilot to descend and, later, leave the fucking controls alone (though, by that time, they were almost certainly doomed), the junior co-pilot inexplicably kept taking control and ordering the aircraft to climb - precisely the wrong to do. What was going through his mind we will never know.