I want to be able to lock a hard drive partition, or maybe a drive letter created using the SUBST command, so that it looks like a CD-ROM to the OS. How can this be done? Is there a DOS command that will do this, or a freeware utility? If you use a utility like FakeCD or Fakedr, will the drive be just like a CD, i.e. unwriteable? I need to be able to test out programs before I burn them to a CD to make sure they can run from the CD.