I typically find that when I upgrade graphic card driver (NVIDIA's driver setup) or change to lower resolution for one or the other reason that the desktop icons move like I don't want them to.
With this solution you can save the desktop icons positions and restore the location of the icons later.
Download Layout.zip (Layout.dll comes from an old Microsoft resource kit and works on Vista 32-bit or Windows XP 32-bit) and copy Layout.dll into C:\Windows\System32 or %windir%\system32. Then double-click on Layout.reg or right click and Merge.
If you now right-click on your desktop you will find the menu options Save Desktop Icon Layout and Restore Desktop Icon Layout.
It's also available if your right-click on the Computer on the start menu.