Older DVD-RAM Archive Discs Showing Empty In Explorer

I have been using DVD-RAM discs for many years to store/archive pictures and other data and have never encountered any problems with them. Recommendations I have seen on the web state that this format is the most robust and reliable DVD format for data storage and that DVD-RAM discs should have a lifetime of 30 years if stored in the right conditions. I recently purchased a new Sony Vaio 'all-in-one' PC with Windows 7 64 Bit OS and I have been very pleased with it.

One of the reasons that I chose this PC was because the optical drive spec included read/write for DVD-RAM discs. I tested this facility straight away and it appeared to work perfectly with new DVD-RAM discs BUT when I put in some of my older DVD-RAM archive discs, Windows Explorer shows them to be empty, although a few of the discs it was able to read OK. I have a lot of DVD-RAM archives but fortunately, I still have an old XP (SP3) laptop which can read the discs.

So, I am in the process of copying all the archived data onto a 1TB Toshiba USB drive from where the new Sony Vaio can access the 'missing' files. The question in my mind is whether there is a fundamental incompatibility between older DVD-RAM discs and Windows 7 64 bit or whether the problem lies with outdated drivers, different formatting of older DVD-RAM discs or some other reasons. I also need to decide whether to continue archiving onto DVD-RAM discs.