I have a large website with many html pages, all developed on the old Adobe Page Mill application. When I try to open any of those html pages onto my new Dreamweaver CS5.5 on my new iMac, those html files are not recognized as "openable" (their titles appear in light gray, and clicking on them does not open them. I can't even click and drag them into the Dreamweaver window. How can I open those old html files in Dreamweaver?
May I recommend you to read this article first to get the basics of "Defining a site" in DW.
This article will give you a head start in Working with DW. Page Mill files are simple text file and they should open readily in DW but who knows what has gone with your system that nothing seems to work.
I did try again, and was able to get DW to open the file. However, it
doesn't look quite like it did in Page Mill. I suspect I may need to make
some changes - so will work on that. I will work with DW instructions in
the link that you sent. Thanks.