A-ha! This didn't take as long as I thought.
My friend was trying to get the hot-swap feature working with his Antec MX-1 enclosure coupled to his Gigabyte motherboard. He was hooking it up to the JMicron controller (which is rebranded as Gigabyte on their motherboards, but JMicron makes it) and the problem was if he hooked up the drive when the computer was on Vista (man, thought this was an older OS problem!) would not detect the drive unless he went into Device Manager and did a scan for changes or he rebooted.
This was not his boot drive & it was using the Gigabyte/JMicron drivers, but it still did not work till he applied the fix outlined in this MSKB article:http://support.microsoft.com/kb/922976
The article talks of this fix is only if the affected drive is your boot drive & you are using the default MS drivers, but once he changed his BIOS to AHCI, rebooted, applied this fix, rebooted once again, and then finally reinstalled the JMicron drivers did his enclosure start acting properly.
And for those who don't want to read the MSKB article, I'll sum it up for you. This behavior is not a bug. It's a feature. Yay!!
Seems when Vista installs it takes it upon itself to disable all storage drivers it thinks the user will never need. If the OS installer doesn't detect AHCI it gets the killbit set in the registry.
Today's friendly tip is when installing an OS always have AHCI enabled even if it makes you have to endure the inconvenience of having to install a driver disk during OS install. Otherwise, your nice SATA drives with all their fancy new features are demoted to legacy IDE mode & treated as IDE drives by the OS which means no NCQ, hot-swap, and all the other cool stuff SATA drives can do.
And a final note, superboyac, just be thankful I'm an email packrat and never delete anything enabling me to bring you this knowledge nugget from December, 2007.