Acrobat X Pro stops working after ~30 days

I have a purchased version of Adobe Creative Suite.  Recently (the past 6 - 8 months), the Acrobat Pro application stops working after approximately 30 days.  Everything else works just fine.  But Acrobat will just shut down when a file is open and then refuse to open again.  I have to uninstall and reinstall the product every time.  I have a product key and it is linked to my Adobe account.  Any ideas how to fix this?  Thanks!