I have a Dell Studio 1537 and all of a sudden it started freezing and buzzing during video playback. This started on 12. Feb 2015.
After spending the last five days trying to fix it by various means I have finally found out what was causing the problem.
On the same day the problem started two programs were installed without my knowledge. They were; Dell Support Assist and Dell Support Assist Agent. After uninstalling both of these from my laptop this has fixed my problems.
I am posting this should anyone else be looking for an answer to the same problem.