I recently ran into an issue with a brand new PC. When this particular user would try to load his corporate signature, Outlook would freeze and go to the white screen. I found this KB article that addresses this issue. It is related to the pre-installed Microsoft Office software package that was causing a conflict with the companies Open License version of the software. The fix was uninstalling the pre-installed version of the software. You have to remove the Pre-Installed Office Desktop Apps.