Occasionally when logging onto particular user accounts on my home family computer the screen resolution changes to a very low setting, making everything very large. How can I stop this from happening? The computer is running Windows XP.

There are a few reasons that the screen resolution could be spontaneously changing when you login to a particular user account. First, the resolution and screen settings for the computer should not be user profile dependent. In other words, the display settings set in one profile should be consistent across all other user profiles. However, I have seen situations whereby the display settings are different between the user profiles which causes problems such as the one you are describing. So you should first check the display settings within the affected profile to make sure they are exactly the same as the other user profiles on the computer which do not exhibit the problem. Begin by checking the settings in the profiles which are not affected by the problem (so you can compare these settings with the affected profiles). Go to the “Start” menu > “Control Panel” and open the “Display” control panel (you may need to first open the “Appearance and Themes” category). In the Display Properties window click the “Settings” tab and note down the settings. Then click the “Advanced” button and you should see the advanced display properties window appear. Click the “Monitor” tab and write down the monitor refresh rate. Click “Cancel” and then “Cancel” again. Now, login to one of the profiles experiencing the problem and check the same settings to ensure they are correct. If different, change the settings so they are all the same and then test to see whether the problem persists.

However, should the settings already be the same (or changing the settings to match does not resolve the problem) you should next try updating the video card drivers on your computer. Visit the website of the manufacturer of your video card and check whether any updated drivers are available. More than likely there will be an update, especially if you have not updated your drivers since the original installation of the video card, as graphics card manufacturers have a tendency to update their video card drivers regularly. Once downloaded follow the instructions included with the download to update the video drivers. On completion, check whether the problem has been solved.

If you find that the problem continues then it may be worthwhile running the Windows System File Checker (SFC) utility to verify whether any Windows files are missing or have become corrupt and could be causing this behaviour. You can find instructions on using the SFC utility within my response to the first question in this column.