How to delete and overwrite a write-protected file?

I would like to make a copy of a file many times while a programme is running. Since this file is write-protected The first copy works but I can't owerwrite the Write-protected file at the second copying. I always receive an error message: accessing denied. The same happens when I would like to delete the file.
I tried to solve the problem like this:

FileCopy("C:\New.txt","C:\folder\New.txt",true)

Thanks!

Why don't you open the original for reading and write the contents to a new file which won't then be write-protected

You are right because there was a txt file in the example.
Actually I would like to make a copy of all the files in a folder by means of a programme. These files are in different extension, for example: bmp, wav, ini etc. Some of them are write-protected and I can't change it.

I've added FileGetAttribute and FileSetAttribute to my FilesEx library http://www.b4x.com/forum/additional-libraries/1844-filesex-library-returns-file-information.html

You may find the Bitwise library useful for manipulating the attribute bit pattern.

Thank you! It may be the good solution but since I have used the free version for now I can't download the file. Maybe later...