I am trying to incorporate a biometric fingerprint reader into a c# application. The dll's associated with the reader hardware are Microsoft.VC80.CRT.manifest, msvcp80.dll, msvcr80.dll and
id3CertisImage.dll. I think to be able to use the reader I need to add these files as references on the project, but this fails with message'...make sure file is accessible and is a valid assembly or com component.'. Therefore I think that I should register these dll's and then I would be able to add them as references. The biometric fingerprint reader I am using is a Certis V1.

You only add COM exposed libraries or managed libraries as a project reference. For other types of libraries you manually import the functionality of the lib (which it sounds like you need to in this case).

Here is how you would call ShellExecute() from shell32.dll in %WINDIR%\system32\shell32.dll without adding a reference:

    private static extern long ShellExecute(Int32 hWnd, string lpOperation,
    string lpFile, string lpParameters, string lpDirectory, long nShowCmd);

    private enum SW
      SW_HIDE = 0,

    private void OpenNotepad()
      ShellExecute(0, "open", "notepad.exe", null, null, (long)SW.SW_SHOWNORMAL);