The last time I was talking about free DVD burner's was with Express Burn. Now it turns out Express Burn is not exactly free. The download is fully working for 14 days. After that period of time it expires and you are restricted to only buring CD's. It's kinda freeware but actually just shareware. Annoying, but fine if you only need to burn audio CD's.
Well anyway, no need to worry! If you want a completly free DVD burner with no restrictions and compatibility with Windows Vista, you should use DEEP BURNER.
It burns CD's and DVD's but not HD DVD or Blu Ray. But it's stable and very good. It actually looks like the front end of that other freeware burner Final Burn - except slightly more polished and presentable.
Go download DEEP BURNER here.
Remember: it's freeware.