About 1995 and the introduction of the REGISTRY in Windows 95 along with DLLs broke any easy way to kick programs back into operation without re-installing said program.
Answer? You get to re-install the programs in question.
Lesson? You may find it better to repair an OS issue than reinstall the OS.
I re-installed XP(home) over itself following a crash, and I can search for, and launch, previously loaded progs, even though they do not show up on the desktop list of progs, or on the start menu. Thus they are still present, but hidden, and require explorer or the search function to access them. Is there a method of railroading these blighters back where they can be seen, please?