Follow these steps
1.Right click on desktop.
2.Select Personalize.
3.Click to open Display Settings.
4.And check your resolution in Display settings window.
5.If you want to change your resolution move the slider to the resolution you want, and then click Apply .

6.Click yes in conformation window.

7.Ok and close personalize window.

• Next Entry: Change or Check your Monitor resolution in Windows Xp