Does anyone know what is going on please? Suddenly all my office products have stopped working. First Publisher, then FrontPage and now Office (Word)

And it is not a normal activation: Instead of extracting a set of numbers for me to read to Microsoft on these LEGAL programs, it demands some install CD and then says it cant find some .msi file?? First pub.msi in Publisher, of which I cant find the CD after 10 years, - but then Office XP Professional demanded some .msi file as well. And when I actually found the old installation cD, it then still couldnt find the .msi file it had said was on it!