I have seen weird hardware problems when the hard disk wasn't connected properly. You should try to connect it the same way, using the same cable, as it was when it worked. Make sure the plugs are inserted all the way in the sockets. Also, if you changed any jumpers on the disk, change them back.
If your computer uses those older, 40-wire of 80-wire, extremely wide or extremely thick cables (PATA), then you have another bunch of potential issues.
Each PATA cable has one plug for the computer and two (or sometimes one single) plug for hard disks or CD drives. On each cable, either
set both devices (or the only device) to Cable Select.
or
set one to Master and the other to Slave.
But just try to leave everything as it was from the beginning when it worked fine, as Windows might have other, unknown, requirements as well.
Also, what did you do with the hard disk on the other computer? Did you change anything? Did you access it under GNU/Linux (Linux) or Windows? Or something else?