So I had a user that was unable to open links in Outlook, they encountered the following error after they downgraded to Office 2007 from 2010 and tried to open links within emails...
This operation has been cancelled due to restrictions in effect on this computer. Please contact your system administrator.
Looks to be an issue with the Default Program settings for opening internet links, so Outlook doesn't know what to do with it.
The resolution is in kb 310049 from Microsoft. Click on the FixMe button for the appropriate OS and after a quick reboot you're back in business, or if you're into fixing it manually the instructions are there as well.