Desktop problem

I have been having a problem with my desktop ever since i went from the mac book to the tv with an HDMI cord.When the Mac is not hooked up to the tv it works fine. Except for my desktop pic is blue.But when i go to put the same pic on the desktop it shows in the settings that its still on the desktop(but its blue).When i plug the mac to the tv then i see the desktop pic on the tv but blue on the Mac desktop.Im not seeing the same thing on both the TV screen and Mac Screen.When i open up a file on the Mac while its hook up to the Tv i have to drag the file out of the Mac screen and the its show up on the tv...weird.Its like theres two different screen but i can only see one at a time,but once again its only when I'm hooked up to the tv. Please help,I'm sure its something simple it has to be its a MAC.Thanks

http://www.mac-forums.com/forums/other-hardware-peripherals/193239-connecting-your-mac-your-tv.html

See post # 2 - Item # 3.