got new motherboard installed but comp keeps resetting!!!

whwen i installed my other hd with xp already installed and tried to access my slave hd a message kept poping up drive is not formatted would you like to format... i couldnt open/explore the contents.

i dont want to reinstall windows and have it not recgonize it as a 300 gig. when i first got the hd and installed it i had to configure and format it to see it as a 300 gig (actually only 279 gig)

 

ok this is what ive done...

i got a HD out of another comp that had win xp installed already. i put it in my comp with new mobo and booted it up. it runs perfectly fine... so far anyways... i installed all the mobo drivers and everything is working. now the HD that i did have in it that kept resetting works perfectly fine as a slave. im waiting for my co-worker to find his xp disk so i can try to install it on the HD that kept resetting.