We've recently had a few queries from RuneScape users who say the RuneScape Windows client is crashing. (Even though it worked fine previously). We haven't changed our windows client recently, and from what we've been told it seems it's actually a recent windows update which is causing this problem.
We believe this problem has now been fixed in another windows update. Therefore if you are having problems with the RuneScape client failing we recommend you visit windowsupdate.com to get the latest patches. This should fix it.