That's one of "couple of driver issues". Install the driver for your videocard and possibly the inf-file for your monitor and everything will be fine. Nothing strange here.
have just done a re-install on an old Optiplex which was behaving strangely, so i reloaded XP and all apears to be fine apart from a couple of driver issues. am back on line, so that's okay. But the resolution is haywire - 640x480 / 16 bit. The slider won't work at desktop properties and XP has obviously chosen some kind of default setting. I did find a list of options for resoloutions but each one was dreadful - ended up with an 8 bit setting at one point!