Couple of things to try. Open Device Manager and see if anything is showing a yellow or red error. Other drivers may need to be updated.
You could also check if any system files might be damaged or corrupted by running a system file checker scan from an elevated command prompt (option two.) If any problems are found run the scan 3 times rebooting in between each scan. SFC /SCANNOW Command - System File Checker
You could also open Vaio Care (should be available in Start > All Programs) and run the built in diagnotics tools.