I got 2 Sony DVD - RW. I had been using this for some time. When it was erased to add new data it became unwritable. Windows XP will not recognise these disks any more. What is the solution? Any software available to make it good.

No this is a usual problem in every re-writble dics it will better to use pen drive rather than using disc. That cd have short life that is why it get correpted