Help I cant get xp to load...

I upgraded my hard drive and used the old h/d on another computer before i got xp loaded on the new h/d... Now if it does boot from the disc, it takes almost an hour just to get thrue the first part. then i dies right as you start the next part. Ive gotten arrore reports, to it only wanting to boot from the bad xp load i just put in.. I am at my witts end.. Please help me.. Jr.