Okay,  my annoying problem is that for some weird reason my ability to change my desktop background has vanished.  It started about 6 - 8 months ago when I was on a website who's name will remain anonymous.  The site was a high def site with high def pics.  I thought the pics were cool so I decided to set one as my desktop background.  When I did that the pic did not display and my screen was blank except for the icons.   I shut down the computer and saw the pic I downloaded right before the computer monitor turned off.  When the computer is turned on the desktop is blank.   Now the only thing I can do is change the color of the desktop.  I can't "tile, stretch or center or choose the currently saved pictures.  I can only change the desktop background by setting a new picture as the background which I can only see for a few seconds when the computer is shutting down. 

 

The latest advice was to set up the computer with the "last known good configuration".  How do I do this?  I tried hitting F2 and F12 during power up and got into the BIOS menu but could not get to the option where I could select the last known good config.   I was also advised to somehow copy this: ( C:\WINDOWS\Web\Wallpaper  )  but did not really understand how to do that either.  In all the attempts of trying to delete potential viruses and programs, I accidentally deleted something that now prevents me from listening to music in Windows Media Player. (s)

 

I have a Dell Dimension 9100

 

Thanks in advance.  Any help or advise would be greatly appreciated.