If you use Firefox, just CNTL - (minus) to get to the right size.
If you are using Internet Explorer, you can adjust the size at the bottom right of the status bar.
Another situation could be the use of the magnifier. It can be difficult to close it because it can be hard to find when the page looks so large. One way to close it would be to go back to your desktop, click on the blank tray and go to Task Manager and close the magnifier.
Hope this helps.
If you can't see the bright side of life, polish the dull side.