This is often troublesome. and occasionally occurs in newer versions of MSIE. This option in MSIE4 and later specifies whether a new process is created for each instance of Internet Explorer that you start. With this setting disabled, all instances of Internet Explorer and Windows Explorer that you start are run in the same process. When you enable this setting, you can prevent one instance of Internet Explorer or Windows Explorer from effecting other instances if it stops responding (hangs); however, if you enable this setting, additional resources are consumed and Internet Explorer’s performance may be affected.
Generally, this option is available on the Internet Control Panel, Advanced tab, but sometimes it isn’t visible. If this is the case, a simple registry change can manually control it.
WARNING: this is a registry change, so please be careful!
BrowseNewProcess = Yes