1996 sunfire 2.2 computer problem

Hey guys, i recently purchased a 96 sunfire 2.2 auto. I knew it had a few issues so i got the codes checked by a friend he said i had several bad sensors but more than likely my computer was the culpret so i ordered a new preprogrammed one from autozone. Before i installed it my car ran decent it just misfired and ran a little rough at times and stalled on occassion. I just installed the new computer hoping that would fix the problems. Wow now my car appears to be possesed by a deamon. My gauges are going crazy. The speedo moves in congunction with the rpms. The car is only running off of maybe 2 cylinders most likely just one. and it is barely drivable. I thought i might have plugged the connectors in the wrongs slots but i checked and they are ok. I also tried disconnecting the battery for fifteen minutes. Still no better. Any help would be greatly appriciated.