Strange problem burning DVD movies, any help?

[superhands]

Hi all, I'm having a problem burning DVD movies that I'm hoping someone can help me with as I'm stumped as to what's wrong...

I used to have no problems at all, I could burn AVI files to DVD just fine and they would play on any DVD player. Now All of a sudden I can still burn them but they aren't recognised by any DVD or Blu-Ray player I've tried.
I was running on XP when the problem first started occuring, so I installed Windows 7 on another HDD and am now running in dual-boot. I tried burning a movie on Windows 7 with a few different programs, same result each time - no error reports what-so-ever but the disc is not recognised by any player other than my computer.
I can still burn DVD data discs and my drive is functioning correctly in all other ways. I thoguht there might be something wrong with my drive though so I bought a new one and installed it, only to find the same problem occuring.
Any help would be greatly appreciated, I'm really confused as to what the problem is.

 

[wanamingo]

Did you get a new style DVD? Some players only like +R's and will in no way take an RW

 

[superhands]

I have 2 different DVD drives now, one IDE and one newer SATA model. I'm using the same brand of DVD-Rs that I've always used. The discs have always worked on all of the DVD players in my house and my Blu-Ray player, so why they're not being recognised all of a sudden is completely beyond me. I can normally figure out these sort of problems myself as I have good computer knowledge, but I've tried everything I can think of, to no avail. Windows reports that both drives are working fine and I get no error reports, the DVDs work on my PC still but the players just aren't recognising them.