if you want the PC for networking and games, format the HDD to FAT32. it is faster (for games) and older OS's (like win98) can read the HDD when you network it
and the XP install is fairly straight forward, the only thing you have to do is enter your name, serial and maybe regional settings. And make sure you have an internet connection when it is installed so you can activate XP
PS. Never give out your serial, especially not for XP