I was able to install (from disk) Acrobat 9 on my new Windows 7 PC (64-bit, Ultimate), but it crashes each time I choose the update. Sometimes it says it needs to add an "installer," but then it crashes again, too.
I have it on my laptop, where there was no problem, and I never use the two simultaneously. Any ideas?
When you have problems from that menu item, simply go to http://www.adobe.com/support/downloads/product.jsp?product=1&platform= Windows and download all the updates after your current version and install them in order.
Sorry, I don't know then. Good luck and maybe some others have run into the problem. Things like being administrator and having anti-virus disabled are typical issues, but I think you have addressed those.
Maybe it has something to do with the Windows installer version that you're using? (I dunno if Adobe uses that or not.). Regardless, I don't think it would hurt to update to the latest version.
Here's the KB article: http://support.microsoft.com/kb/893803
You also might want to try turning off your anti-malware package during the install, and turning off User Account Control.
Open Control Panel. Open User Accounts. Click on Change User Account Control Settings. Push slider down to Never Notify. You may have to restart your machine for this to take effect. (And you should set it back to where it was if you're subsequently successful in the install.)
(As an FYI, I'm having a bit of an issue with multi-page PDF's opening in an IE9 browser session after upgrading Acrobat v9.45 to v9.50, so you might want to see if you have that issue too.)