Sorry, but this is not a solution, merely somebody else with a similar problem.
Environment : No-name desktop PC running Win XP SP3 with Reader X used both within Firefox and stand alone.
After viewing PDF files either within Firefox or stand alone, my WIndows Task Manager shows that AcroRd32.exe is still running. This doesn't cause any problems when the process is created within Firefox, but if the PDF file was local and had been viewed via a stand-alone instance of Reader X, the orphaned AcroRd32.exe soaks up all the CPU time. I then have to end it's process tree to regain use of my computer.
This is a very serious problem, so I'm puzzled as to why no-one before me has commented on the first post, which was made a month ago.
From reading the initial post from Jul 14, this Adobe Acrobat reader problem has been ongoing for many years and many releases. I noticed the AcroRd32.exe taking up all available CPU ( 100% ) on my uniprocessor machine. Using the Task Manager to reset it's priority to LOW helped but only terminiting it relieved my CPU load.
Why would Adobe not fix this problem? When you search the web with Google, AcroRd32.exe was referred to as a virus in some cases and safe in others. My AcroRd32.exe is a recent version of Adobe Reader X and has a valid digital certificate signed be Verisign.
So, again, why has Adobe not fixed this problem?
Perplexed and annoyed.