Screensaver not working - solution and cause(?)

[Followup-To: set to microsoft.public.windowsxp.general]

Excuse the X-post, but this question has been asked numerous times in
several NGs. Please honour the Followup-To:

My screensaver stopped working ~1 month ago. I discovered that it would
work if "Wait" was set to 1 or 2 minutes but not if it was 3 or greater.

Google Groups showed plenty of people with the problem but no definitive
solution. One post mentioned something about the Power settings so I
took a look at mine. Home/Office Desk was the selected scheme; just to
make sure I hadn't customized it (the settings were 20min, Never, Never,
Never) I opened the scheme drop-down picked Home/Office Desk (i.e. the
current scheme). The settings didn't change (confirming that I hadn't
customized it) but the Apply button became enabled. I clicked Apply,
then OK. The screensaver has been working properly since :-) I guess
some registry settings were screwed and Applying the Power scheme forced
them to be re-written perhaps?

As to the cause, I don't _know_ for certain but around the time the
problem showed up I installed 3 screensavers from 3Planesoft
<http://www.3planesoft.com/index.html>; Watermill, Lantern, and The One
Ring. All of these are more than a simple .SCR file and use an installer
so maybe screwed up the registry settings?. Watermill is a trial version
in which the saver only runs for 90 seconds (there is a countdown timer
on the screen); could this be using/interfering with the timer that
Windows uses to start the screensaver? 90 seconds, 1.5mins, and it was
OK at 1 or 2 minutes? Coincidence?

I also installed Webshots <www.webshots.com>, or more precisely, I
upgraded it to the latest version. As well as cycling the wallpaper it
also has a screensaver which is enabled when the s/w is installed. As
well as adding Webshots to the screensaver list in the Display dialogue
it also can be enabled/disabled from it's Options dialogue (which also
gets invoked by the Settings button in Display) so interacts/interferes
with the Windows control. Again, could this have screwed some registry
settings?

Hopefully this (the Power Settings thing) will help others with the same
problem and, maybe, point towards the cause?

HTH

Regards,

Parish