to answer your questions
Adobe (and others) get a kickback from Google for every download of Chrome
On the other point, the download may have completed, but the installation didn't. Maybe something you did, maybe a minor problem with your PC
Several ways round it
Either download from the ftp site and manually install:
ftp://ftp.adobe.com/pub/adobe/reader...1012_en_US.exe
or
uninstall the Adobe reader and use the Foxit reader instead
Secure PDF Reader
or
uninstall the Adobe readeer and use Amazon's Kindle software