I mentioned before that I have a small sample project that was written in VC++6 that attempts to enumerate available COMM ports under Windows and shows the results. I found the project directory and made a ZIP file of the contents. It is a small MFC Dialog based application that compiles to a standalone EXE file. Here is the link to download the ZIP - VC++6 EnumComm Project

I also have done a reasonably equivalent program in VB6. This was built using VB6 with Service Pack 6. This means that even though I produced the EXE file it most likely will not run on your computer unless you have the full VB6/SP6 already installed. So best is to re-build it. I used come SP/6 controls so you either need to get that from the MS web site or re-select controls from an earlier service pack. A note is that the MSCOMM from SP6 seems to puke on COMM port numbers over COM16 so even though the utility tries to scan from 1 to 100 many of the latter port numbers are rejected by MSCOMM. Here is the link to download the ZIP - VB6 CommScan Project

Have Fun
Michael Karas

PS. Please use these as a starting point. I do not wager anything on the suitability or capability of these programs to find all COMM ports installed in your computer. Note that these programs will not show ports that are already in use by another program. So do not expect to get an ALL PORTS list like you would get in the DeviceManager window. (BTW. Obtaining that list is not a trivial exercise for even a super experienced Windows programmer and I have seen much discussion on the subject on various web forums).
MJK