Windows 7: Adobe Reader 9.4 doesn't open

I have Windows7 and Adobe Reader 9.4 just downloaded however, I can't open a PDF directly from IE8 (I had the 9.1 version with the same problem so I uninstalled it and tried 9.4 - no luck!).
I have been on several support forums and have tried the following advice to no avail:

1. Disenabled the Adobe PDF Link Helper
2. Automatic configuration turned off
3. Display PDF in browser button turned on in Adobe Reader settings.

Nothing helps!
PDF files saved on my computer open but there are PDF files that I can only open directly from IE (I can't save them.)

Any advice? Will an older version of Adobe Reader help?

Double posting is not allowed. We do not have a rule on triple posting.

Reader settings seem OK (set to load in browser), Browser helper plugin lists in IE (good), then are the full active x controls for adobe reader registering properly in IE?

Post 26 onwards from the following site has various suggested fixes, which may or may not work for you: Adobe Forums: "Cannot use adobe reader to view pdf in...

Hey guys i want to know how to crack an pdf written in Adobe but locked by password & i guess lost the password???? Any idea how to go about doing that???