Ok, finally found the culprit on one of my machines.
I did NOT have the PCM or DVDLauncher services installed or running on my computer but I DO HAVE a service called PDVDSrv.exe (in the \\...\program files\Cyberlink\PowerDVD\ directory running on startup. After disabling that service, my...
After I posted the message above (about the screensaver not working with the MS Optical Mouse 3000), I found the following KB article from Microsoft that acknowledges this as a problem with their Intellipoint software and some other services (dealing with DVD playback). See knowledge base...
I am having the exact same problem with my new MS Optical Mouse 3000 on two PCs in the house (purchased 2 at the same time).
The screen saver will only come on if I press Win-L or lock the workstation (eMachine - WinXP Home). Then, after the set amount of time, the screen saver does come on...