Computer reboots after hard drive install

[whsacastel]

Well i have a dell optiplex 160L which i bought for $35, the lady who sold it to me says her old hard drive crashed which is why she is selling it. I have an HP pavilion a250n which works perfectly fine, the dell came with no HD so i decided to try it out with the HP hard drive, but when i start the dell it boots to a screen with 5 options: start windows normally, safe mode, safe mode with command prompt, last good known configuration, etc. So i select start windows normally and it reboots only to come back to the same screen again. It will do this over and over, What can this be? i checked the RAM in my HP and it works fine so the only thing i could imagine is that it does not like my hard drive off the HP

 

[Lowndsey]

you cant just pop a hard drive into another system and expect it to boot unless their are very similar hardware configurations. You need to reinstall your operating system onto the hard drive in the dell.

 

[whsacastel]

oh i see so i can just buy another HD i actually need that one for my hp thanks so much