His BIOS is probably set to AHCI mode (or parity Raid) and yours is in IDE mode. IDE does not allow hot swapping.

sata drives are refered to as ide based on how they are connected, therefore anything other than ahci or raid would make it ide.

To run ahci you have to set it to ahci in the bios when load windows however there is a registery hack than allows you to change it to ahci and then reboot, enter the bios and set it to achi.

But the best is to just set it up when you load a fresh copy of windows.

[QUOTE]
If you want to change ide to ahci without reinstall windows os, you need to change the "regedit"
Just info on switching IDE -> AHCI
To resolve this issue yourself, enable the AHCI driver in the registry before you change the SATA mode of the boot drive. To do this, follow these steps:
1.Exit all Windows-based programs.
2.Click Start, type regedit in the Start Search box, and then press ENTER.
3.If you receive the User Account Control dialog box, click Continue.
4.Locate and then click one of the following registry subkeys:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV
5.In the right pane, right-click Start in the Name column, and then click Modify.
6.In the Value data box, type 0, and then click OK.
7.On the File menu, click Exit to close Registry Editor.
8. Reboot to bios and change to ahci.
[/QUOTE]

Or FixIt:
http://support.microsoft.com/kb/922976/en-us

Also, there is probably a "ENABLE HOT SWAP" option in your BIOS for your HDD's. Sometime this option will not appear if not set to AHCI/RAID.
I have a P8P67 mobo and that's how it works. I'm guessing it's fairly similar with your board.