------------------------------Which Chip? Well, it depends on which set of thieving b@stardz you choose to support: The ones who use insider trading to enrich themselves while running their company into the ground, or the ones who illegally pay vendors to not support the first group.
Reply to Scotteq
You should always install the older OS first if possible, installing xp after W7 will mess up the bootloader for W7, which will need to be repaired from the W7 boot disk.
An alternative way to do it, would be to disconnect the W7 drive and install XP on another drive. After completion reconnect the W7 drive and use the bios to select the drive to boot from, you would need to do this each time you want to change the OS. If you only switch occasionally this could work for you.