Microsoft Visual Studio 6.0 installation problem - pdm.dll

I finally managed to resolve this nagging problem. First some background. I had Visual Studio 6.0 installed on my machine and at some time I installed Visual Studio .NET 2003 without uninstalling VS6.0. When I went back to uninstall 6.0, I got an error that said some .stf file was not found. So, I thought, installing VS6.0 again (to repair) and then uninstalling it would clean up the system of any 6.0 residues. This was not to be. I could not install 6.0 even when I uninstalled VS.NET2003 completely. I consistently got this error "pdm.dll was unable to update the registry" following which the installation would fail.

I deleted the VS6.0 folder in "Program Files", and also manually cleaned up the registry of any "visual studio" refereences. Still when I installed, got the same set of errors. To resolve the problem I had to rename pdm.dll in two locations - "C:\Program Files\Common Files\Microsoft Shared\VSDEBUG7" and "C:\WinNT\system32" to pdm.dll.old.

However, the above two renaming were not direct. While renaming pdm.dll in the former path, I got access denied error. So I ensured that I changed to a user who had administrative privielges and this resolved the access problem. However, to be sure, I wanted to deleted VSDEBUG7 folder altogether. To do this, I renamed the folder and then restarted the machine. After this I could delete this folder.

Renaming pdm.dll in the latter path posed another problem - explorer.exe was using it and so OS would allow neither delete nor rename operations. So I opened command prompt window, killed explorer.exe and then used the "ren" command to rename the pdm.dll file. After this I restarted Windows and installed VS6.0. This time the installation went fine.

Hope this post will be useful to people who encounter similar problems with pdm.dll.