First try running Windows Updates and see if it fixes the problem for you. To check for updates:
Open Windows Update by clicking the Start button. In the search box, type Update, and then, in the list of results, click Windows Update. Then, in the left pane, click Check for updates, and then wait while Windows looks for the latest updates for your computer.
If Windows Updates doesn't fix the problem, try searching for drivers here - http://esupport.sony.com/perl/select-system.pl
(Sony support, as zerovit suggested).
Microsoft Windows Outreach