CD-R's suddenly "unreadable".

I've been listening to CD-r's on my CEC TL-1X without any problems for the past several years. Within the past few weeks the same CD-R's have become unreadable on this transport. Ocassionally, if I start the CD on a later track, say track 10, and work my way back to track 1 with the remote, it will read and continue to play.
The manufacturer of the CD-R's are from many sources including Sony, Marantz, IBM, etc.

I checked the laser for dust and debris and all seems OK.

Any Suggestions??

Don't know if this is relevant to your situation but thought I'd pass the info along. -- Recently I asked Dan Wright of ModWright to do some mods on my CAL Delta transport. He said he was reluctant to do so since he felt that the laser in a CDP/T had a useful life of 5-8 years. I'm currently having the laser/transport mechanism replaced along with the planned mods.
I suspect it is the laser transport rather than the laser diode that "wears out."
My Levinson No. 39 has been doing the same thing, and since it's under warranty, I'm letting the factory figure it out...should be back in a week or two. Maybe they will tell me why it was happening.
I have commented several times about the instability of CDR's, "see vaporware". These are not archival mediums! Depending on the storage, age and plain deterioration of the CDR, it could be disc's going bad! IMO, this is a serious concern that should outrage every consumer, but it appears nobody cares about throwing their money away on something that will last maybe 1-3 years.

.......and you thought cassette were bad.

Make sure your disc can be read on other machines before you blame the playback deck.
News Flash: The RIAA has developed and secretly deployed new Satellite Technology capable of emitting low level radiation that effectively wipes out all CD-R's - when asked about this the RIAA said that recent laws passed by Congress allow the RIAA to take "whatever steps necessary" to protect copyrighted material. When pressed about the long term effects of the radiation and the recent reports of chickens being born with four legs - the RIAA commented "Not only has the RIAA effectively delt with copy protection, but we have also doubled the productivity of poultry farmers everywhere."

In a related story -
You should probably clean the laser. The pits are not as deep on CDR's and therefore are harder to read. My Sony is not supposed to play CDRW's but it does but it occasionally has to be cleaned in order for it to read them.
This is an elusive problem because it can be a lowered output from an aging laser, misalignment, tray movement problems or the fact you are burning the CDRs at 16Xs or 24Xs which seems to present problems with some players. I would first have a tech go through the player and establish output, alignment and all before blaming the CDRs.
Good Luck.
It's very easy to clean the laser with a cleaning disc or remove the cover and clean it with a QTip. Then try the other fixes if it doesn't help.
I burn a lot of cd-rs for the car. my head unit (blaupunkt) heats up during use and often makes my cd-rs unreadable halfway through. I believe instability of cd-rs are to blame. if you examine them, they are thinner than normal cds. the maxells i've used lately seem to have a half-life of only a few weeks of car use, the philips cd-rs seem to fare better. i have to burn new discs every month or so...btw, i also have a cec tl-1x and it plays 'new' cd-rs just fine--as long as they're less than a few weeks old.
Seems like Maxell does cause more problems than most CDR's.
The Imation discs seem to work well and are cheap at about .30 each. I also like the Fugi's.