Need to re-install Acrobat Pro from CS6. I think it's X but that didn't work. And 11 gave me error messages when I tried the trial version install. Where to start?

I uninstalled Acrobat Pro a few months ago and had trouble re-installing it then. It was crashing every time I opened a pdf.

I've since had my operating system re-installed. I just downloaded 11 and 10 for Mac. I'm on 10.9.5 Neither would install.

I have plenty of memory and hard drive.

I thought I would just use the trial version until I could figure it out, but that wouldn't work either. It said the installation cannot proceed because some of the processes are running. I shut everything down first and still got this message.

Any hints?