I have Illustrator CS6 installed on my Windows 7 64-bit computer. Recently problems begun with copy and paste. When I open a drawing and select an object, I can duplicate it by copy and paste it (I know, select Alt-drag is a more elegant way to duplicate objects, but old habits die hard). Copy and paste normally works the first time I am using it after I have loaded Illustrator, however, when I repeat it, select the same object again, I can't paste it anymore. Apparently it has not been copied into the clipboard again. This error occurs most of the times, but occasionally the copy and past function works. I could not work out any pattern that would explain this, with the exception that text is always copied, so this problem does not apply to text elements. Even, if I select a text element together with the path that won't copy, it also works, both elements together are pasted.
I would like to add that I completely re-installed Illustrator, which did not change anything, and that I have no app installed that would manage the clipboard.
Any help would be appreciated!
Andreas