Video playback / authoring problems

[Stark]

I've lately begun encountering problems with video playback and DVD authoring. Divx gets stuck at random points and stutters, DVDs authored with Nero always lose video/audio sync, usually have corruption, etc. These files are stored locally, and I save authored DVDs to images before burning. It's becoming rather frustrating: the files aren't corrupt, but they don't play properly anymore and I haven't authored an error-free DVD in weeks.