I am going to assume you mean a PC.
I use Icon Restore. A free utility. You need to get all the icons in place first bit it will bring them all back if they are lost or repositioned due to screen size changes.
http://www.pcadvisor.co.uk/downloads/index.cfm ?categoryid=1499&itemId=25934
Icon Restore
Icons don't stay put like they should. With Icon Restore, you can order them back to their places. After installing Icon Restore, you can save the icon layout. Then even if you change the screen resolution, you can call your icons back from their wanderings