Originally Posted by Burky
A similar thing happened to me today.
I have my pc working great. I tried out an old hard disk I have lying around, which I wanted to throw away or sell, and it was a busted pos.
So I went back to my other disks and unplugged the broken one. It wouldn't boot. (though no BSODs)
I reloaded the BIOS defaults and it worked fine again. Weird.
I doubt it's fried though, as that makes no sense unless you knocked your old hdd around whilst installing the new one. Try reloading defaults.
[EDIT]
Check that all your drives are recognised; it should say so on post, and you can also check in the BIOS.
Make sure you plug your drive into SATA port 1.
And sorry to ask the obvious, but make sure you plugged in the old disks into the exact same point as before; if you change master to slave, or something else like that you might get problems.
Failing that, see if you can install Windows on your new SATA disk.
If you can, then once in windows you should be able to access your old disk too. It's best to run your OS off a faster hard disk anyway.