Welcome to PCHF Geri K
installed xp onto HD from another pc, which reads the HD fine.? on switching on, it trys to start windows but getting blue screen (stop: 0x000007B ) boot error.
When you installed windows onto a hard drive installs motherboard drivers and places key entries into your registry for that specific motherboard.
So when you move the hard drive to another machine with a different motherboard you will more than likely get an error like you did. (this happens 99% of the time)
Could you answer some questions which might help us pinpoint the problem?
Do you get an error message when installing windows or does it just restart?
At what stage of the setup does it restart your machine? e.g after (loading network, video card e.t.c)
Was your hard drive blank (formatted) when you tried to install windows?
Also make sure that you have setup your motherboard correctly e.g. if you have placed an additional PCI Sound Card in that you have disabled the onboard in the BIOS e.t.c
***EDIT*** Could you also confirm whether your motherboard is the Gigabyte GA-K8NS