Sleep and Power Management in Windows Vista

I run into a problem that my laptop cannot wake up after sleep / hibernate, I try many different settings and combinations in power management of Vista and no luck, so I suspect it is related to my recent installation of KB939979 or KB938194?!

Nevertheless, I searched a couple of articles & tools, and also the differences between sleep (S2), hybrid sleep (S3) and hibernate (S4) in Windows Vista. My resolution is... update the latest version of display driver in Vista then problem gone. :)