I have had the same problem in Excel and Word, and using Ctl+C for copy, if the selected are had dotted lines around then all copy functions worked, if it was just a solid line, then just a simple paste was available, not the paste special. Occassionally,
holding down these keys to flush out the cache also worked, but that also caused the program to close. My system is W7 Enterprise 32 bit, with IE9 and Google Chrome, Office 2010.
Uninstalling Skype Click to Call seems to have solved the problem.
Unfortunately, I don't know how to link back to Hans's post (see middle of page 4), so I will have copied and pasted his reply below.
Skype has released an updated version of the Click to Call browser add-on that should be free of the problem mentioned above.
If you want it, go to [http://www.skype.com/intl/en-us/get-skype/on-your-computer/click-to-call/windows/](http://www.skype.com/intl/en-us/get-skype/on-your-computer/click-to-call/windows/) and click Download Now.
Once I removed my old Click-to-Call, and installed my updated version, my problems disappeared. So if you like the functionality, just get the updated version installed.