From a previous note in this forum . . .
Another place to look in Windows XP is the DPI (dots per inch) resolution in the Advanced area of the Display settings
Right mouse click on an empty area of your desktop and select Properties. From the Display properties tab select the Settings screen. At the bottom right, click the Advanced button.
From here, on the first screen that comes up (General), there is a DPI resolution that should be set to Normal size. If it is Large size or Custom, then this can also throw off window orientation.
Also note on this screen in the bottom half is the place to set when Windows will apply new display settings (ie is a reboot required). Perhaps after changing settings you had to reboot the computer for them to take effect.