|Recheck ide cable and drive pins, |
Re-check jumpers. Might have to remove jumper for m/s.
Some bio's have in other area a detection for drives. Might look for that even if first page says it is there.
Might have to reset bios. (I don't mean flash unless some 127G limit issue or chs limit which I doubt in your case)
Replace drive or test in other system even if desktop with adapter.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10