This has nothing to do with your monitor settings as suggested above, it is a windows setting!!!

Right Click on a blank piece of your desktop, in that menu select "Graphics Options" > "Graphics Properties.

That will open a Pop-up Menu, you'll need the 5th tab which says "Rotation" and select the option you want from there.

You can alos try holding down <CTRL> + <ALT> + Any cursor key and that will rotate your desktop too (Up = Upside down, Down = Normal, Right = 90 deg clockwise and Left = 90 deg anti-clockwise)

Hope this helps
 

If it don't works don't blame me coz its not suitable with latest video cards...................

aaj se me tumhe log Gaurav the Great ke nam se jane ge....

 Thanks for the Info Gaurav the Great