file problems

I have a server which was temporarily used by an outside person to store files. They accessed through FTP – pernmissions weren’t set right. Many of the folders and files they created show no name in windows and I can’t seem to delete or rename or do anything to them. Does anyone know how to delete these, short of wiping the drive? This is a Win2k server, with NTFS partition. I tried running a chkdisk , but to no effect.
Thanks