GOOD: Firefox 3.6.16 is running fine (with the anomaly reported previously that tab names appear with a special character at the end represented as a solid bar)
BAD: PDF Xchange 2.0 Build 54 will not install. After choosing English as the preferred language it reports an Error pane of "This program requires Windows version 5.0 or later". Both the full package (PDFX4.exe) and the viewer only (PDFXVwer.exe) react the same way.
UGLY: Making the change recommended by RodgerOver in post 898516 to get past installation barriers did not help (temporarily change Version and VersionNumber at HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion from "Windows 98" and "4.10.2222" to "Windows NT" and "5.20").
Something is awry because:
The only other reference to PDF Xchange was in a response....
.... to which I could find no reply.
PDF Xchange Build 54 must be checking more than CurrentVersion in the registry, but have no idea how to discover what it is or come up with a way to fake it out.
There is nothing in the Wiki about Xchange.
A copy of Build 47 would help determine whether the cause lies with the Build 54 or if something on my system is interfering with discovery. No luck so far in obtaining a copy.
Given the depth of experience in this thread I am hopeful that there is an answer to be found.
Any ideas out there on what might get me past the Error pane will be welcome indeed.