Stuttering Payback on Panasonic

Hey. This is my first post but I really do need some help. I have a Panasonic NV-GS400 (now 18 months old - I didn't get an extended warranty), but both the visual and audio are stuttering on playback. It seems to record fine - for the time being. I've had quite a bit of usage in both recording and for editing. But I'm stuck right now.
Can anyone help? Thanks.