Win xp install on a Dell

I am reformatting a comp for a friend. When he gave it to me it had Win ME on it he wanted Win98 put on it and had an old 98 disk. After reformatting and installing Win98SE I could not find drivers for modems(Dell site lists about ten different modems). Asked if he had any disks and he brought me about ten disks. None were a ME reinstall disk but one was a XP reinstall disk. I'm wonderingconfused if I can put XP on with this disk but There is no Activation code so I'm guessing it either doesn't need one or is for another comp which he says they don't have any other Dell's(Thank God )

 

From what I have been told by the guy (small repair shop owner) who replaced my hard drive, is that Dell's do not need key codes IF the install disk is a Dell disk

 

I don't think the XP Pro corporate version discs had one either.