Ok...
if you put the 300gigger as the master you will have to format it. Then install windows from the begining. You just can't take the c: drive which is now the master and has all your programs on it and just make it a slave and exspect xp to work. Why not just make the 300gigger the master on the second IDE channel? Also you have to make sure you computer's bios will support a drive that big.
My advice is to take it to a shop and let them do the work.
if you put the 300gigger as the master you will have to format it. Then install windows from the begining. You just can't take the c: drive which is now the master and has all your programs on it and just make it a slave and exspect xp to work. Why not just make the 300gigger the master on the second IDE channel? Also you have to make sure you computer's bios will support a drive that big.
My advice is to take it to a shop and let them do the work.