How do I overwrite or erase data on a CD-RW disc?

[DonKiddick]

I am a relative newcomer to this technology so please be patient and treat me gently...
I have bought a number of blank CD-RW discs in the belief that once I had used or part used them I could then either copy over the data or delete the data and thus essentially have a blank disc onto which I could copy new data. I have tried to do this and got either a "Disc full" or "Can't delete" error message. What am I doing wrong?

[Fitzer]

Your burning program should have the option to erase CD-RW somewhere in it.

[matty34]

once you have copied a disc you can delete it or put more on there,

if your saying you cant put document or programmes on it, it could also mean that you have a wrong disc for it or you need to get a more mb cd

hope it makes sence

[SteveSxx]

This is incorrect
a CDR - you can add to nless closed
a CDRW is rewriteable (in whole) but cannot be added to.....