Responding sometimes doesn't work

I have windows 7 and up to date internet explorer and not a big fan of firefox, not sure why. Anyway, sometimes when I go to respond to threads, the bar doesn't start blinking for me to type. What type of error is this? To make it work, I either refresh the pages a few times and if that doesn't work, I restart internet explorer. Also on this internet explorer, you can change the settings to compatible view and that seems to work also.

Any idea's? I don't want to throw my laptop thru the window.

Thanks.