@lokutus25 Thanks for your help. After trying everyone's suggestinos, I was still having Acrobat issues, so I tried uninstalling Acrobat, Air, and the C++ runtime libraries.  (When I upgraded to the 2008 libraries, I noticed that the previous version on my computer (2005) was still there.  So, I uninstalled both versions.)  Then, I installed the 2008 C++ libraries, followed by installing Acrobat Reader X (and its payload of Adobe Air).  Everything works fine now, as far as I can tell.  Hovering the mouse over a desktop PDF file does not throw a runtime library error, and the Reader plugin in Firefox works fine too. I am not using the Windows 2000 compatibility either. BTW - Your English is fine.  Thanks again. ... View more

Chosing the Windows 2000 compatible mode partially worked for me.  But, I still get the Visual C++ runtime error.  However, that doesn't seem to crash Reader. Even with that fix, I can only open a pdf file by first starting Reader, and opening a file from within reader.  (In other words, if I double-click on a .pdf file from within Windows, it crashes.  I am also finding that my Acrobat Reader plugin for Firefox 10.0.0.396 still crashes when I try to view a pdf file in the Firefox browser. I think I'd like to just install a previous stable version.  Can someone advise me on how to do that (specifically, where to find it).  I was upgrading from Reader 7, and removed it from my machine before I downloaded Reader X. What a cluster! Thanks. PS, since I installed Reader X, I now have two identical copies of Adobe Air on my computer, according to the Uninstall manager.  If I uninstall one, will it further mess up my system?  Do I need Adobe Air to use Reader? ... View more