I just spent an interesting couple of hours troubleshooting an Outlook 2007 problem. Whenever this customer opened any calendar entry, or tried to create a new calendar entry, Outlook crashed.
I tried a lot of normal things -
Run Install with Repair option
Turn off Outlook cached mode and rename outlook.ost files
Run all Microsoft updates at update.microsoft.com
Run Outlook with /cleanviews and /cleanreminders (Start, run, type in outlook /cleanviews is a good one to try)
Uninstalled SnagIt, which I had read on a forum had helped a similar problem
Deleted the Outlook forms cache - frmcache.dat in case it was corrupted.
After all this I was getting annoyed at the problem. It was starting to get personal. I did some general web searching on "outlook crash calendar" and finally just "outlook crash" as my keywords. I came across a page asking if someone tried running Outlook in safe mode. I googled "Outlook safe mode" and you run it with Outlook /safe. I saw a page that said if you can run Outlook in safe mode try deleting the file outcmd.dat and then restart Outlook.
That did the trick. Now I have a happy customer who does not have to re-image their laptop, and I am happy that I won the battle.
Here's the helpful page I found and a little excerpt:
If Outlook starts normal in Safe mode, Check one of the following:
The outcmd.dat file in the application data\microsoft\outlook folder might be corrupt.
1. Rename or delete this file while Outlook is closed.
2. When you restart Outlook, the folder will be recreated.