I've seen this. The installer forgot motherboard drivers and/or other odd things.
As an example of installing XP on a machine that came with Vista, read http://www.fastfs.com/help_pages/hp%20downgrade.htm
Who would know to do all that?
have 2 msi netbooks, one with xpsp3 and one with sys7. bought usb kybd (gear head kb4700tp). kybd works fine with sys7, but xpsp3 will not acknowledge usb kybd. wants to install but fails.