I have had a number of calls recently regarding being able to paste tables and such within word and excel, this one was a strange one to work out and took me a while before I came to the conclusion that it was good old Mr Skype, what basically happens is that you can still paste but it will only paste basic text, no formatting or anything special just basic text and that is it, sometimes you completely lose the ability to paste but this is only very rare cases.
If this has happened to you the first thing to check is that Skype Click to Call is installed, you can check this by going on to the internet and just checking anything on google that has a number next to it you will see is looks like the image below.
If you see anything like the above image then this will be the offender, To remove it you can simply find it in the control panel in Add Remove Programs, if you uninstall this it has no effect on Skype itself it just removes the click to call feature.
Once it has been removed restart your computer and you will notice that you paste features are back to normal once again.