HP 300n DVD will not read disk

I can make a DVD but my drive will not read it. Neither
will my son's computer.
I have used HP DVD+RW, HP DVD+R, Imation DVD+RW, and
Maxell DVD+RW

I don't know what is wrong that the disc that it makes
will be be able to play in my drive.

Also I use a RW disc above that I have written to and the
drive says that it has media on it and asks if I want to
write over it. I say Yes and it comes back and says it
is not empty.
I also try to erase it and it shows that it is erasing
but still not able to rewrite to it.

HP 7695
DVD 300n
Record Now 4.5
IE 6.0 all updates
Power DVD

My burner will play commercial movies etc. but will not
play anything that I write with it (data, or any files)

Anyone have any idea what is wrong.

HP 300n DVD will not read disk