Windows 8 copy-paste problem

Hello,
I have a very strange problem. In my work I have to copy information from a field in a PDF file and then paste it in a HTTPS secured web page field. Sometimes everything works fine but there are times where every second copy-paste is not working and I'm not pasting anything. This started happening after I installed windows 8. I'm doing everything as I should so where is the problem?

I've looked in the net and some people suggest that the problem may be in the coping from an unsecured PDF file into a secured HTTPS webpage. However nobody suggest any solution if this is the problem...

Please help! Thank you.

Kind regards,
Katherina