Interesting to be the very 1st person to ask a question about this issue. I used the search window above as I have for many computer questions I have had in the past only to receive the very same "no results" message.
I googled it and there is a great deal of post dedicated to the problem "mseinstall is not a valid win32 application" with a lot of chase your tail answers.
I was wondering if I might have a piece of malware causing the issue.
I have ran rkill, superantispyware, spybot, malwarebytes, adware cleaner, MRT.exe, combofix, and SFC thus far. (all current and updated versions of the aforementioned)
What should I try next?
Is there already topic on this that the search will not find?
Probably just me, but I never have any luck with the search on this site.