A couple weeks ago I upgraded from Microsoft Office 2007 to Microsoft Office 2010--at least I tried to upgrade. It seemed like a routine upgrade process until I tried to open Outlook 2010 and was greeted with a message saying something along the lines of "Please wait while Windows Configures Microsoft Office Single Image 2010."
I had no idea what the message meant, but it could not be ignored. I was able to get Outlook to open by starting in Safe Mode (which you can do by holding down the Control key on your keyboard as you start Outlook). Running Outlook in Safe Mode allowed me to do my work, but I had to remember to use Safe Mode every time I started Outlook and none of the customization I'd done to my preferences was functional.
After struggling with this problem for hours, I got in touch with Microsoft tech support. He went through my computer and deleted any remnants of legacy versions of Office, and spent hours doing who knows what else, but to no avail.
There is an option when installing Office 2010 to customize the upgrade process to only upgrade certain programs. Hypothetically I could have just upgraded everything except Outlook 2007. But, alas, Outlook was the only program I could not opt out of. Eventually I gave up on Microsoft support, uninstalled Office 2010 and just reinstalled 2007.
Two weeks later I was finally given a solution that I would like to pass along to anyone having this same Microsoft Outlook 2010 upgrade problem. The actual fix takes only minutes. All you need to do is download Microsoft Windows Search 4.0 for Windows XP (KB940157). Reinstall Office 2010. And you're done. Outlook 2010 (as well as the rest of the Office suite) now works perfectly for me.