To get back the "show desktop" icon do the following:

•Make sure "Quick Launch" is enabled

•Right click on the taskbar and then click on "Properties", and a box will pop up.

•Under the taskbar tab, check the option that says "Show Quick Launch" and then click on "Apply".

•After you are done with this, click on "Start" and then click on "Run". A small box will pop up on the right hand corner. If any text is present, delete it and type the command "regsvr32 In Ii: U shell32" in the open box without the quotes. Wait for a couple of seconds and you will see a small window, which says "Dliinstall in shell32 succeeded". Now, you will be able to see the "Show desktop" icon again.