A second hard drive that can be used for storage....yes.
A second hard drive that can then have a version of Windows installed on it...yes.
A second hard drive that already has an O/S installed on it from a different motherboard...yes. But that drive will be accessible only as a storage drive, not as a boot drive. None of the programs installed on that drive will run as they ran in the other system.
And the jumper settings need to be correctly set for its position on the cable connecting it to the motherboard.
Seagate Technology - ATA Jumper Settings - http://www.seagate.com/ww/v/index.jsp?loca...000dd04090aRCRD