Switching the HD into another computer would work, so long as you reconfigure the jumpers so that the HD was a slave, not a master. Then the computer ought to boot from the master as usual. If it doesn't work, then you can format the boot sector of the hard drive so it doesn't get in the way. I can find the command for you, but I have no idea whether it would format the rest as well. I'd have to test that for you to make sure, if it gets to that.
Installing another OS would also work, but probably not Windows. You need something that gives you a lot of flexibility in the installation as to what to put in the boot sector.