Facing TV Problems? Ask a TV Technician.
There's 3 separate devices that can cause your problem -- Netflix, your DVD player OR the TV.
It sounds like you reset your TV, but that DVD/Netflix juddering points MORE to the DVD causing both and possibly affecting the Audio problem too.
I'd start with resetting the DVD player...then the TV to see if the juddering disappears. Also turn off any energy saver or video enhancement settings specifically on your TV set only, as I have seen those cause problems with numerous customers.
Here is the DVD reset procedure -
That should clear out any issues you have with picture and sound, if it doesn't reset the TV, and see if the DVDs still cause juddering. Lastly see if Netflix is still causing problems and if so call Netflix and have them reset your Netflix account.