In my opinion first install Linux and then windows XP that will help you in booting your system wiht LILO and then you can have dual booting wiht LILO. As SDK said, installing XP first will set your drive with FAT and if after that you install linux it will be partitionless installation and that will cost at speed of your system also the booting will be done through a floppy which i think you won't like. Same thing happened to me then i did as i said. Now everything is woking fine.