This is a reply to anyone still having trouble with copy/paste.
Have you checked your Virus protection settings? I found I had change the settings in Webroot (the virus protection I installed) to give access to each of my different applications so I could use Copy/Paste. I have Windows 8.1.
I thought it was a Windows problem but it is actually related to Webroot in my case. I am sure there are others who posted on this thread that they had the same problem with different virus protections.