cdrom is recognized but can’t read disk

I HAVE A TDK CD-R-RW & A BACKPACK CDR-RW. BOTH WERE WORKING FINE FOR ABOUT A YEAR. NOW BOTH ARE RECOGNIZED BY MY COMPUTER BUT, I GET AN ERROR MESSAGE WHEN THEY TRY TO READ A DISK. WHAT DO I DO TO RECOVER. I CAN’T REINSTALL MY WIN98SE BECAUSE MY DISKCAN’T BE READ. HELP!!!