Looks like XP SP2 screws with the video drivers of older systems, particularly LCD screens that have a limited range of resolutions and refresh rates they can handle.
Working on an old Dell Inspiron with 14" LCD screen and Intel 815 family graphics adapter.
Whenever the laptop boots up into windows, the screen goes black and can only be recovered by hooking an external monitor to it and hitting Fn+F8 until Windows properly displays on the LCD, or alternatively, I can boot up in VGA mode.
So now, I'm doing a "repair" install using SP1 and won't be installing SP2 on this laptop anytime soon.
Couldn't do a rollback since XP was installed using a CD that had SP2 rolled into the base install.