Problem reading CD-Rs recorded at 2x

Hello,

I have a set of 40 CDs that I recorded three years ago on a HP CD
recorder at the highest speed that the drive would support: 2x. These
are all HP brand disks.

Now I find I cannot read any of these disks on any of the higher-speed
CD readers (40x to 52x) or recorders (16x to 40x) that I have access
to: Asus, LG, etc.

I still have the old HP recorder and when I connected it up, I found
that I could read all my 40 CDs on it. I am now going through the
painstaking and timeconsuming (and boring!) process of making copies
of these CDs on high-speed recorders (at 10x).

Any thoughts or comments?

TIA,

Kim