Old RW disks, Not detectable by burner?

I’m using INcd i have been for quite some time , a while ago i formatted some CDRW’s, 1
TDK RW and a few Matrox RW’s. I also had some data on them, nothing to important. I’ve
since reinstalled everthing on my hardrive and recently noticed these CD’s are completly
undetectable by my TDK Velo CD burner. My dvd drive detects them, confirms
they have 656mb of data but cannot find any files. I’m almost certain this isn’t a
problem with my burner because when i bought these TDK RW’s in question i only formatted
the one mentioned in this text earlier. Tonite I peeled the packaging on the other TDK’s that where purchased with the unreadable one and
my burner recognized all of them and asked me if i wanted to format ? do i ? was this a
mistake in the first place to format ? i cannot retrieve the date from the old ones
what’s to stop me from losing the data after i format and burn the new ones ? i
dont’ understand this. is there a way to go back to the the old disks and do an Uber
format that will wipe everything out allowing me to use them again?

i’m using windows 98 also 400 mhz processor (will upgrade when doom3 comes out)

all the various cd erasers, nero for one will not work because my drive does not detect
these disks, and prompts me to insert the disk when it already is.

Cd-R’s burn fine.