iTunes Error 7 and missing *.DLL file after updating iTunes

EVERY SINGLE TIME I update iTunes I have go through a lengthy process of uninstalling and reinstalling everything Apple on my PC. Every single time for the past couple of years. I have a Windows 8.1 Laptop which works just fine as far as I can see but every time I update I get the same (or similar) set of errors.

Sometimes I find a specific "solution" from a forum somewhere that involves deleting a file from here and adding one there and sometime I have no choice to completely erase all trace of Apple apps on the computer and start from scratch.

Right now it's this and I'm in the process of uninstalling and re-install again.

Another hour of my life I won't get back.

Any clues from anyone - I assume that this doesn't happen to everyone but I'd like to know how it can be fixed - it does seem to be quite common though but every response I see from people is to uninstall and reinstall. Hardly a root cause analysis of the problem is it?

Thanks...