Is it possible to plug in both internal and external hard disks at the same time and run them at the same time, also is it possible for both of them to have two different OS, like one has XP the other has Windows 7.
you can connect any number of internal & external hard drives as long as your bios support & available connectors..
but you cant run more than one OS normally, for that you have to go any of virtualization products like
virtual pc or virtual box, or vmware..
virtual pc & vitrual box is free & limited features..
if you need more option go for VMWARE , which give vmware server for free(needs free registration)
or vmware workstation which is commercial product..
It is possible but not advisable to have both an internal and external bootable hard drive installed. If you wish to run both Windows XP and Windows 7 have you considered using XP Mode? To learn more about XP Mode, please see the following link: http://www.microsoft.com/windows/virtual-pc/download.as...