If your screen resolution is set to the same as the website has optimised its content for, it will display correctly. If there is a mismatch, it won't. Simple as that. It's the best that can be achieved in the complicated and variable world of computing! LC.
The problem is not your computer but the fault of those who created the Webb page. They have written the script for a higher resolution monitor and failed to set it to auto change to the resolution that you are using. You could try the next res up from 800x600 to see if it's better