I am having the exact same problem. The site works fine, then the next time it is totally fried.
I AM NOT RETURNING TO THIS SITE FOR AT LEAST A WEEK AND RECOMMEND THAT EVERYBODY DO THE SAME. The problem is very sophisticated and it is simply not worth the risk. God only knows what it is trying to install on your machine! (to emerge later when you least expect it).

RCU, PLEASE DEAL WITH THIS. It has gone on too long already and there is NO EXCUSE any more. If you can't control the site, you should temporarily close it down!