I have spent a whole working with the customer support at Adobe attempting to resolve the inability to install Acrobat X. I purchased the Master Collection CS 5.5 and as part of the total package, Acrobat X is included. All products installed except Acrobat. I uninstalled the previous version of Acrobat installed (9 Pro Extended). I uninstalled all previous versions of Master Collection and still no closer to a solution. Any guidance would be helpful. Have tried installation with a new administrative account. Have run the installation under Selective Start mode in Windows. I am running Windows XP SP 3. I don't know what else to do.