Converting back to long filenames

Because of a major problem (WinME),I had to copy the contents from one folder to another drive using the dos copy command. I had every thing else on my system backed up on CDs but this folder containg some 1100plus entries was too large to put on a CD. Now my system is up and running well. When I copied the folder contents back to my ‘c’ drive all the filename were truncated. Is there a way to convert them back to the longer version?