"The file 'C:\WINDOWS\Downloaded Installations\{5AF1D19F-9DA3-4176-9962-6F964989EE57}\BOINC.msi' is not a valid installation package for the product BOINC. Try to find the installation package 'BOINC.msi' in a folder from which you can install BOINC."

Did a search for *.msi and found BOINC.msi in folder C:\WINDOWS\Downloaded Installations\{5AF1D19F-9DA3-4176-9962-6F964989EE57}. Pointed the installer to that folder, but now I'm getting this error:
"The file 'C:\WINDOWS\Downloaded Installations\{5AF1D19F-9DA3-4176-9962-6F964989EE57}' is not a valid installation package for the product BOINC. Try to find the installation package 'BOINC.msi' in a folder from which you can install BOINC."

Now what?