Problems Changing wallpaper

[Jamesreeves_2007]

Basically I bought this second hand desktop computer from a shop, got it home and the background is very stubborn and wont change, when i right click a picture and select "set as desktop background 99% of the time the background will remain the dark blue colour sometimes half of the picture will appear and 0.1% the picture will appear.
My specs are:

40GB HDD
512MB Ram
1.80GHz Intel Celeron Processor

Please can someone help

 

[Mattu]

The Operating System (OS) you're using would be helpful to know also.

Have you tried the settings "Stretch" or "Tile" yet under desktop properties?

 

[johnb35]

Does it have a fresh installation of windows on it or is this some old machine that they were given to sell to someone? Most likely there is so much junk on that machine that its needs to be wiped and reinstalled.

 

[jamesd1981]

give the machine a thorough clean out with likes of ccleaner, then a defrag, and instaed of just right clicking a picture, go through the control panel, appearance, then change desktop background, point it to the pic you want and click.