try a little house cleaning
first off if the pc a few years old try running cc cleaner and defragler to clean up some drive space. on the viao update the video and sound drivers and then update your dvix software or dvix codac pack that your using. if it still has the sound lagging the video use a program to read the codac info of your avi and see if you need a missing audio codac a lot of movie avi are compres with a lot of codac to shrink there size.if you dont have the right one or yours is out of date it going to cause your pc to lag or look like it lagging.
Does an ursine quadruped void wastes in an arboreal environment?