Adobe Acrobat 9 Pro stuck at "preparing to install"

After getting the total runaround from both phone and chat support, I'm here hoping someone can put an end to this problem.

I have had Adobe Creative Suite 4 installed for quite a while now. Recently, Acrobat had been giving me error messages, saying it was installed as part of a suite, and I needed to open another program to activate. That never worked. Neither did the repair utility or any other suggestion I found online.

So the logical next step is an uninstall and re-install. Problem is, now I can't re-install. The process never goes past "preparing to install." I even tried copying the contents of the disc to my desktop and running the installer to no avail.

I also tried downloading the trial installation files from Adobe's site, and selecting the "I have a serial number" option. However, it said my serial number is invalid.

All of my other CS4 programs work fine, and I really need Acrobat back up and running. Can someone please help me?

Thanks in advance!