Copy and Paste Problem

I have noticed recently in the last couple of months that when I use copy and paste in the text box editor it hangs the program completely and I need to kill the webpage and go again.

This only happens in the visual editor if I go into the text editor it does not cause any problems.

this problem occurs when I am in the | text block editor | and try to copy and paste from other programs or elsewhere. I can replicate this nearly 100% of the time in the visual tab but in the text tab it never happens. The causes some sort of overload to my computer because I can hear the fan kick in after about 30 seconds in this hung screen.

Nothing is responsive until I close my browser and start again no amount of waiting can help.

Any ideas please ?