Reading DVD's to copy


I have made DVD’s for a couple of years and recently have tried to copy them. Some were made with Sonic MYDVD and others were recorded with an LG DVD recorder. About half of thos recorded with the LG can’t be read. I get an error message part way through the reading. This happens with a Phillips DVD burner on my laptop, A Sony DRU-810A and a sony DRU-530. I have tried Record Now software–DVD X-COPY–DVD SHRINK. Can anyone help–I want to make copies for my son of shows that I have on DVD. The DVD’s all play on my computer and 3 other players. I’m almost sure this is a hardware problem.

Probably they have decreased in quality over the time.

Try to read them slower in various drives.