I'd also suggest Grisoft AVG free, though I really don't know how good it is. I do know that it's not as invasive as McAffee, and it's free, so...
Anyway, page files. My version of XP can't boot without a page file. At all. It requires a minimum of 7MB in order to boot, otherwise it'll crash and reboot with windows managed settings.
As for bios updates, how would you go about finding out what your board is if you don't have the packaging? I know it's an MSI, and a socket A, but beyond that, no idea.
