Hi rnemtb,
NkMC2 is Nikon Message Center 2 which is supposed to look for updates to your Nikon software and camera firmware.
As of now, to determine that the pop-up is due to Nikon message center, test the issue in safe mode.
I would suggest you to try the steps mentioned below.
Step 1: Test the issue in Safe mode
http://windows.microsoft.com/en-US/windows7/Start-your-computer-in-safe-mode
Step 2: Perform a clean boot
If the issue doesn’t occur in Safe mode, then a startup application is causing this error. Put the computer into a clean boot and then test the issue. Visit the link below for the same.
http://support.microsoft.com/kb/929135
Note: Once the troubleshooting is over, reset the computer to start as usual.
Step 3: Uninstall or change a program
If you come to know through clean boot method that Nikon message center is causing this issue, then uninstall that program only if you’re not using it. Visit the link below for the same.
http://windows.microsoft.com/en-US/windows7/Uninstall-or-change-a-program
Step 4: Perform an online virus scan
http://onecare.live.com/site/en-us/default.htm
Hope this information is helpful and let me know if you need any further assistance.
Mouneshwar R – Microsoft Support
Visit our Microsoft Answers Feedback Forum and let us know what you think