OUtlook 2010 won't open links until after reboot

After searching on this topic and finding other link problems discussed, I didn't see anything addressing this specific problem. Hopefully someone here has already seen and fixed this issue.

I'm running Windows 7 Home 64-bit with Office & Outlook 2010. I have automatic updates activated and am using the Windows firewall. AV products are McAfee, Spyware Doctor, and MS Security Essentials.

The problem is that, when I click on a link in Outlook, the link doesn't open the browser. There is no error message, just the scrolling color bar that is supposed to indicate something is happening. I've tried waiting several minutes to see if an error message would come up, but haven't seen one yet. Eventually, I shut down Outlook and reboot the system.

Upon reboot, when I go back into Outlook and click on the same link, it works every time. Once the computer has been up and running for a while, the problem reappears.

Any ideas on root cause?

Thanks,
Bill

I just did the repair process, so we'll see how it goes. Thanks for the suggestion!

The repair process did not solve the problem. This morning I went into Outlook and successfully clicked on some links, but then I left the computer for a while with Outlook open and, when I came back, I could no longer get links to work.

Here is some additional system info for my computer:

The problem may be solved, but I'll wait a couple of days to declare victory.

Today, I scanned the system with MS Security Essentials (full scan) and didn't find any problems. I also tried to scan the system with Spyware Doctor but could not launch it because of a missing file. The service was still running so I had to stop the process. At that point, I elected to uninstall Spyware Doctor and install the free version of Ad-aware. I then scanned the system with Ad-aware and didn't find anything major, but did find one low-risk threat that I deleted.

Since then, I haven't had any issues with links working from Outlook even though Outlook has now been open for several hours. I suspect that the problem with Spyware Doctor is the actual root cause of the problem, but I'll wait to see what happens tomorrow and Monday.