It may not.
Till XPsp1 there was no support for wide screen, only if you load integrated XPsp2 or sp3 then you will find that the onboard graphics will detect it once you load the mobo drivers.
I faced this problem bcoz when I bought XP it was with SP1 only so I had to borrow a CD from another source to load the XPSP2 version then onwards it worked perfectly.
Vista does not have that problem at all.