Use the Long/Extended test, and if the test finds nothing wrong with the drive, test the RAM modules with a bootable CD containing Memtest86. Download the CD Image (ISO file) from here: http://www.memtest.org/
Use IMGBurn to create the CD from the ISO file: http://www.filehippo.com/download_imgburn/
Boot your PC from that CD and the RAM test will run automatically and continuously until you press the <ESC> key. Four passes is sufficient to reveal any RAM errors if there are any.
Test each RAM module on it's own so you know which ones (if any) are faulty.
Thanks. I found that I am able to use "xcopy" as long as the destination is not on the same drive…
but there are lots of files and directories, so I would rather fix the drive that is giving the CDC error.
Drive will read, but not write, rename, or move files to anywhere else on the same drive.