Can't change desktop background?

There are many reasons that this no longer works, and not a whole lot of good reasons for this to happen. The best way to solve this problem is start by identifying why you can no longer change your backgrounds. Competing Programs Many graphical programs and some browsers have special security software integrated into them to protect their content and images from being manipulated or copied. While these programs are active, they will prevent all attempts to screen shot images, set desktop backgrounds or use third party software that captures media. You must completely close these programs out and check the Program Manager to ensure they are not running in the background. Network Security Windows NT versions as well as Windows 98 and above have networking security features to block users without sufficient privileges from setting the desktop background. The reason for this is a security loophole that exists that would allow knowledgeable users to exploit this to make other unauthorized changes to the computer. The only way around this is to contact your immediate supervisor or your IT service in order to gain permission, or have them make the change for you. Copyrighted Images An undocumented feature of Windows Vista and Windows Media Center 9 and above includes additional protection for copyrighted media. Images that have these flags activated will prevent you from making copies, inserting them into documents, linking to them and even setting them as your desktop background. If you do own the image, you always have the option of opening it with a third party editor such as PaintShop and saving the image as a jpeg or gif which does not contain security information. Viruses There are numerous viruses that exploit your computer and in effect lock you out of certain areas. There is an exploit in Windows that can be used to gain control over certain areas of your computer. If you notice other symptoms or areas you may not access, you should immediately treat your computer and network for viruses. This includes updating your virus software from a secure or trusted source. If you have trouble doing this because of the virus, download a free virus software and updates such as AVG to a flash drive and run it from that device. Image Replacement If you have write permissions (you can save files) on your computer you can change any background image. You must locate the directory where the current background image is stored. This can be done by right clicking the image and finding target or running a search from the start menu. Once you have located the image, replace it with your new background which you have renamed to be identical to the old one. This effectively replaces the old one without having to go through your network administrator and wasting his time. Good Luck