videos with no sound on chrome

I am having a issue with sound on my flash player. When I played a video from website like YouTube and others, I don't hear any sound from the video. I don't know what happen, it used to worked until earlier this week, when it stop working. I try several of the your step regarding with flash player on google chrome and in particular sound problem, but nothing seem to work. If someone out there have any tips or solution for this problem, please let me know as soon as possible. Thank You!

Flash player version -20.0.0.267

Google Chrome (PPAPI) 

Windows (XP) (32-bit)