2 Sony Optiarc Drives not reading DVD

Having problems with an AD7241 and AD7261 optical drives. They read CDR ok but neither of them will read my Verbatim DVD-R discs or write to them. One is over 2 years old and the 7261 is just over a year.

They both display same symptoms of head moving in and out many times trying to read the disc but without success so I cant write to the discs.

Have tried cleaning the lens with a cleaning disc but no joy, anyone else had problems with sony optiaric opticals? What's the best make? Couple of years ago had similar problems with 2 Samsung drives, no drive seems to last over 2 years despite samsung 3 year warranty.

Further playing finds that after about 5 head movements back and forth when booting from a Verbatim disc it reads and boots. Could it be the batch of discs, I always understood Verbatim to be a good make?

Can DVD-R discs go off? Just got some TDK DVD+R today as a trial. The newest drive read it straight away and the oldest drive took 5 head movements before it identified the disc.