desktop picture won't change and cannot click on desktop

Hi, I used to have one of my own photos as my desktop background picture, but one day it was replaced with a blue background. The dock is still visible and programs work fine, but I cannot right-click on the desktop background, or click on icons like Macintosh HD. I have tried to change the background picture - it lets me click on a new picture and displays it in the preview box, but it does not actually change the background.
Any ideas on how to fix this?

Cheers, Tom.

Try some of the steps here: http://www.mac-forums.com/forums/os-x-operating-system/93819-basic-os-x-mac-troubleshooting.html

Thanks D3v1L80Y, repairing the disk permissions worked.

And the amazing thing is the number of times one still reads Repair Permissions does absolutely nothing!

harryb2448 said:

And the amazing thing is the number of times one still reads Repair Permissions does absolutely nothing!

Click to expand...

And I was just reading one of those a couple of days ago.