Unopenable CD files

Hello,
I have stored a lot of valuable work related information and data in over 100 CDs in the last 20 years of working. Until recently, I had no problems in opening them and copy the required files on to my PC. Once in a way, I failed to open a file with an error message 'Cyclic redundancy..error' or something like that.
Many of the CDs were burnt with Windows 95 (between late '90s and early '00s), and the typical CD drive speed was 8X to 16X.
None of the CDs have any visible damage / scratch marks, etc. I have taken care of them storing in proper CD folders.
Now, though I can open the folder list and even file lists in each folder after considerable wait, am unable to open any file or copy - the CDs keep turning (can hear them!), the hour glass does not vanish; the selected file / folder stay selected; nothing happens! After a long 30 min wait, I get the message '....' is not responding.
My present PC has XP and it is a CD - DVD RW drive. Dont know its speed.
I cant afford to loose the data in my CDs.
Need help and advice on how to open; the best way of keeping these backups in an easily accessible device.
If I loose the files in them, it amounts to 'work related' amnesia - I am sure you guys / gals understand the seriousness.
Please help , fast.