Recently my movie files don\'t play in sync with the voices on my external drive

Have you updated your video drivers lately? Or have you added any new apps since this problem started?

I haven't updated my video drive, but have installed some recent anti-virus and spyware. I did this because my computer was acting strange. The malwarebytes found several threats and they were removed. It still does not help with the playback of the movies.

Should I update my video drive? How is this done?

An active scan while playing video would certainly cause the issue you had.

What make and model of video card are you using?

realtek or legacy

Neither of those refers to a video card. Should be with Intel, Nvidia or AMD/ATI

What kind of computer (make and model if possible) are you running with what OS and what software are you playing your videos on? It could be that your video card is outdated or your capping the CPU or RAM.