You cannot simply move a hard drive with a windows install from pc to pc. One, the hardware is different, so you have all the wrong drivers installed, second, the install is licensed to the original pc, it wont re-activate if it is an oem version of windows.
Okay thank you I was unsure as I must of got lucky moving it before from a computer to computer. Yeah guess I will be loosing out on the new computers license then oh well. Thanks for the info.