Acrobat Pro vs Reader

Question

1. Where does Adobe describe the compatibility (or lack thereof) between Reader and Acrobat?
2. Problem History
a. On Win7-64, had Adobe Reader (v9?). Worked fine as app or from browser.
b. Then installed Acrobat 9 Pro Extended with Pro 9 Extended as default for opening PDFs. Worked fine as app or from browser.
c. About 11/4 I was auto-notified of Reader updates & installed them. Reader version shows 9.4.0.
d. Since then trying to download/read PDFs in browser is unsuccessful with "blank question-mark" error.
3. Elsewhere for question-mark problem Graffiti said: "be sure and have only one version or Reader OR Acrobat installed."
Which raises the general questions:
1. Are Reader & Acrobat compatible? (I had assumed so.)
2. How can one have installed the superset of the most recent Reader & Acrobat updates without the 2 products tripping over each other?
3. Where (if anywhere) does an Acrobat user-guide or knowledge base article tell Acrobat Pro users what to do with existing Reader when installing Acrobat, what to do to keep updates from one product from interfering with the other, etc?
Even if I switch to pdf links opening in app rather than browser, I prefer to have the option either way, so I don't want to just abandon the browser capability.
If I uninstall Reader entirely, will it remove even Acrobat's reading capabilities?
All I want to do is have the full range of reading, writing, and other capabilities available.

Answer 1

You said in your post:
"However, web browsers are somewhat notorious for getting confused when their plugins change and update, so it's possible that when the two plugins updated, your selection as to which one is active has been corrupted, leaving neither plugin operational. You should be able to correct that with the options/preferences within your web browser itself."
If this is true, that is why many users, and I am one of those, do not install both products on the same system. I do not dare to try installing Acrobat Reader because of this situation. When I tried it in the past, I got all kinds of strange error messages such that my ability to access PDFs from the web was severely hampered. I could not even start Acrobat itself at times. Why can't Adobe fix this problem?
When you say changes preferences in the browsers, which ones in what browsers? If a Adobe could put together a list of browsers and their preferences that have to be changed, that might help.
Ken Friedman