I was using my ibm computer when i noticed that my mouse wasnt moving very well. So i shut down the computer disconnected the old mouse and plugged a spare one in. When i rebooted my computer a message came up saying 8603 Pointing device error. When it had finised counting the memory it took me into the bios. I noticed that next to the word mouse it said not installed. So i changed it to installed and saved and exited the bios. When the computer restarted it did the same thing and when i went back to the bios it had reverted back to not installed. So i turned off the computer again and reconected the other mouse but it still didnt work.

Any suggestions on what might be wrong?

(You did plug the mouse into the mouse jack, not the keyboard, right?) The PS/2 connector or the controller is probably bad. Try a serial or an USB mouse instead.