I wrote this without realizing you solved your problem -- but here's the advice anyway, for others with a similar problem:
I have an HP Pavillion dv5t and am using Vista, so my suggestion may not work for all of you, but it's worth a try, right? Try going into your Screen Saver settings and changing the settings to select a different Screen Saver. Save your settings and re-boot your computer. Then go into Screen Saver and select your old Screen Saver (the one that stopped working in the first place.) Save and re-boot again. Hopefully the problem will be solved. Sometimes there's just a corruption kind of glitch that can be fixed this easily.
I got the same problem with the worst effect my screensaver been stop working and the worst is when I click or push any button it keeps freezing with nothing black screen and nothing happen then I need to turn it off and restart it because the system was freezing is there any solution to this ? I don't seems got any idea to this problem