i'm guessing it would come up with some errors about drivers and devices that it can't find anymore and then possibly not recognize some of the current stuff. i mean, it might boot up, but then again, it might not.
you'd get a 2.5" external enclosure for a hard drive. what it is, is basically a conversion from the 2.5" pata interface to a usb connection, which then goes into any computer and is recognized as an external hard drive. normally, they are about $10-20 or so.
and rereading your original post, it seems like one of the drives you have is pata and the other is sata, and therefore will have different connectors. they are not interchangeable, and for the drive to be made into an external, it would need to be pata, as sata interface external cases are not as common. which drive (toshiba or dell) has the ata connector (http://images10.newegg.com/NeweggIma...148-073-03.JPG
) and which has the sata connector (http://images10.newegg.com/NeweggIma...6-227-02.JPG)?