Burned dvds wont play on

Make your DVD player compatible to playback DVD-R or DVD+R then you will burn just that format or try to playback on different DVD player

i have begun having a problem with my  4-5 year old bose 321 system.  sometimes dvd's burned on my computer will not  play on my bose 321 system.  sometimes they will.  what's up with this?  it's not a bad media problem.  i've narrowed it to the player.  sometimes i'll play a computer burned dvd on the bose and it will play fine.   next time i try to  play it it won't any ideas? thank you in advance mike