Might be helpful to post your mobo specs, and the video card specs/brand.
I think Windows XP is detecting two ramdacs (graphical processing units), so you may be dual monitor capable. Just see if you have two jacks on the back, either one onboard, (the mobo I/O jacks) and one on the vid card, or two jacks on the video card itself.
Past my bedtime, wish I could help more. You might try logging on and running
Belarc Advisor
and post your system specs for more help.
I think you just have a conflict with the software, causing the default resolutions to load each time you boot up.