Nero Vision and NEC 3540A Sound Freeks out at random

Hello,
I am trying to isolate what my issue is but currently I have been using nero 6.6 with Nerovision 3 for months for burning dvds. I hvae had no issues untill a week ago. I burnt a dvd for a friend of his home movies. For no reason durring the video the sound stops and goes to a HIGH PITCH HUM/Whine that is multiple times louder than the normal sound. It goes like that for an undertemined amount of time then starts working again.

I checked his dvds and they were having issues. I burnt the dvds from mpeg files that his camcorder makes since it has a harddrive in it. I burnt created the dvd again in Nero Vision tryed again and it was fine. So I made him another dvd that had worked fine the first time. This time its sound freeked out. So I saved the compaliation this time. Burnt it again worked fine second time no sound issues.

I thought it may be the compression I was using to get so much video on a disc or an issue with his files. Well last night I burnt a tv show that I save. I have many episodes no issues. All the suden last night this video freeks out. Same issue. I have no idea whats causing it. I have shut down anything I can think of on my pc that may cause the issues like my Ghost backups and such.

Right now I am tring to use another piece of software to isolate it to Nero or not. Its random though some discs are clean some arnt but the frequency is getting more often. Any help or ideas appricated.

Blake