Ian said:
The desktop uses .bmp files only. Convert your jpegs to BMP and copy
them to the Windows directory. They will then appear in the Desktop
list.
It's simply not true that the Desktop only uses .bmp files. I can't
remember the last time I used a .bmp file as a Desktop background.
Superhero - Take a look at these things and see if any of them apply to you:
1. Go to the Display applet in Control Panel and look on the Desktop
tab. Click on Customize Desktop, and then click on the Web tab. If there
are checkmarks next to "My Current Home Page" and "Lock Desktop Items"
uncheck them, Apply/OK out.
2. If you can't enable desktop backgrounds after a virus, MVP Kelly
Theriot has a fix. Look under Wallpaper-Desktop-Disable Changing here:
http://www.kellys-korner-xp.com/xp_w.htm
3. If Display tabs are missing, run Kelly's registry edit on line 285,
right-hand side "Restore all display tabs".
4. Check to see if these Registry entries exist:
HKCU\Software\Microsoft\Windows\CurrentVersion\GroupPolicyobject\{21A7BE9D-5027-49C1-B6F7-757B707E1C94}User\Software\Policies\Microsoft\Windows\System
If "GroupPolicyRefreshTime" and/or "GroupPolicyRefreshTimeOffset" are
there, then delete them.
HKCU\Software\Policies\Microsoft\Windows\System. If
"GroupPolicyRefreshTime" and/or "GroupPolicyRefreshTimeOffset" are
there, then delete them and then run the reg fix from Kelly's page.
5. A default wallpaper called wp.bmp may be set in
HKCU\Software\Policies\Microsoft\Windows\System created by the
smitfraud.c virus. Remove that and you will be able to choose different
wallpapers.
6. For inability to change wallpaper after malware, here is another key:
Hkey_Current_User/software/Microsoft/Windows/CurrentVersion/Policies/Explorer,
Malke