ok so i have 2 hard drives one is 80g the other is 30g and my computer broke a while back so i had to fix it myself so i had to reinstall a OS on it and when i did it made the 30g the boot drive and the 80g has no boot drive and i just bought a computer but it doesn't have a hard drive so what i wanted to do was use the 30g as the hard drive but when i take it out the 80g wont boot on my computer that i fixed cuz it has no boot drive i think idk so my question is how do i add a boot drive to the 80g keep it running by itself and take the 30g put that in the other computer and keep it running by itself so i can have 2 computer running and if it helps to know they both have os systmes on them the 30g has windows xp and the 80g has windows 7 beta ver.7227 but the 80g cant boot without the 30g hard drive being attched

HHHHHHEEEEEEEELLLLLLLLPPPPPPPP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!:4-dontkno