Do you mean the 'browser' disappears? Does the browser close down or has it minimized to the Taskbar?
Please give more details of your system as asked for in red above each posting box.
I am having an unusual problem with my Windows XP computer. Occasionally when I am on a web site (any web site) all of a sudden the web site will disappear and the desktop will show up. Can anyone figure out how to fix this problem? Thank you very much.