I have experienced several freezes in the system. Each time it takes about 5-10 seconds and the the system start normal again except for videos (mainly on Youtube) in which, the video turns green (just a green screen) and I get an error message stays for 2 seconds that says ( the graphics drive has stopped .... I couldn't read the rest). I noticed this freeze after updating the driver about two weeks ago. My graphics card is NVIDIA GeForce GT 540M. BTW, I can't Roll Back Driver.
It's VPC-F22C5E and I got the update via VAIO update centre,. So, uninstalling and then reinstalling would get me the same driver software. Unfortunatly, the system restor is disabled because System protection is turned off and I couldn't turn it ON.
I assume that you installed the graphics driver update (NVIDIA) - 220.127.116.1193? If so try the original driver Version 18.104.22.16880 – available from here – listed under pre-installed drivers and utilities.