When copy and paste doesn't work it can be very much an inconvenience, especially for those that use it a lot. One option, because some programs won't use the copy and paste function with the mouse, is to use Control C to copy and Control V to paste it. To some people, using the Control Copy and Paste function is actually easier and more of a guarantee than using the drop down menu. The problem
. could be a keyboard logger or another pest so you should run a virus scan and try a spy bot as well. You can use an online virus scan at http://housecall.trendmicro.com/us/index.html.