Copying to CD hangs

I don't know if this is the proper NS, but any help would be appreciated.
Running Win 2000 SP4, IBM Net vista, 256K mem, 40 Gig HD. When copying data
files from my C: drive to the CD R W drive, some files begin to copy, but
stop at various points. Using Adaptec software, "Direct CD". Some files
copy fine, but some start the copy process and "hang" part of the way
through the copy process. When I try to reboot the computer, I get an error
message that Windows is working on a file and please close it. I have to
hard shut down the computer and restart to clear the coping process.
Any ideas?
Fred Dwight