I run XP on a laptop and the resolution isn't what it should be; for example, I can't see the gridlines on Excel (despite them not being "unselected") and certain areas in Chrome webpages aren't visible. Difficult to explain, I know.
I have adjusted the resolution via the control panel (to the maximum) but this makes no difference.
Start with the obvious. Go here:
http://reeddesign.co.uk/testcard.htm
If you can't see all of the numbers, from 0 to 10, on both of the numbered lines you need to adjust your [i[monitor's[i] settings. (Follow the on-screen instructions)