For some reason the screen saver Photos in Windows Vista stopped working.
I think this is related to Nvidia's driver because it started after upgrading but I have not able to confirm this because when I installed the old driver the problem persisted.
It says "an error is preventing this slideshow from playing"
http://support.microsoft.com/kb/944221 didn't help.
I have tried the tip to delete any of these files to no avail.
%userprofile%\AppData\Local\Microsoft\Windows Photo Gallery\Pictures.pd4
%userprofile%\AppData\Local\Microsoft\Windows Live Photo Gallery\Pictures.pd4
This can come up in Windows Photo Gallery and sometimes it just helps to manually browse through all images and then try the slide show again.
"An error is preventing this Slide Show from playing."
The solution for the slide show was for me to prevent Windows Photo Gallery from using hardware to accelerate image rendering by setting ForceSoftwareRender to 1 on the following registry location or you can save the two rows below to a .reg file using Notepad and then Run (Merge) it.
[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows Photo Gallery\Viewer]
"ForceSoftwareRender" = dword:00000001
To activate hardware set the value to 0.