Why does Web Enablement randomly quit working for some users and continue to work fine for others?

When logging into JDE using a web browser some will experience a logon screen like this...

Instead of this...

When the empty screen appears the font size of all of the menus stays very small no matter how big the window is made. The session is also unstable and will eventually need to be restarted. Once this starts happening to a person on a computer it has not been able to be fixed by a java re-install, profile reset, browser cache clearing, or any other means. The same user may have no issues at all on another computer. The blank screen will usually be proceeded with this error and then the browser must be refreshed to get the blank