What software are you using to write and erase the CDRW?
What error messages are you getting?
What version Windows?
"what is read only file mean can't delete" I assume you are trying to Delete files from a CDRW using Explorer. You can't. The files are stored on CD as Read Only. You can only remove them using the Burning Software (nero, Easy CD)
Please slow down. Explain the situation fully and clearly...