Install XP first, then install Linux. What distro are using? Sounds like your boot loader is the problem at this point.
i installed linux first -pinguy, then xp. I think it will be the boot loader.
And no, wont boot from disk,
when you power on as laptop for example a Dell, it will normally come on with a screen saying dell, intell etc. press f2 to enter set up.
Nothing comes up at all, it goes straight a grey ish screen, WHICH is the colour of the pinguy screen when its loading the OS,
Theres nothing I can do as I cant get into the bios. Help is greatly appreciated!