Be careful

I purchased a Magnavox unit for $158 plus tax. It worked great, but the DVD was not compatible with moast DVD players. I tried it in five different machines at friends houses. I called Magnavox and was told that can happen now and then???? I bought a Dazzle unit, but found out it is not campatible with Windows 7. I am hoping for an answer with this forum question. Good Luck.