Microsoft Office Problem

I have a system that takes 3-5 minutes to open any file for office when the file is double clicked. When you load the program up from the start menu, it will open quickly, but still take forever to open a file. I have tried a registry clean and defragment. Does anybody have any other ideas? Thanks for the help in advance! FYI, to open outlook with a 4gb pst file takes about 10 seconds…