This is an informational post to my fellow ranchers. (I searched JavaRanch to see if this was already posted elsewhere, but did not find any hits.)
There was a problem with the first publicly released builds Java 6 Upgrade 2 (aka 1.6.0_02) JRE (Java Runtime Environment). The associated Java Plug-In will cause Internet Explorer (IE) to consistently crash. You do not need to be actively using a Java Applet or JWS Application for the problem to occur. So in other words, the JRE Plug-In wasn't even running. Therefore, this issue will affect anyone that installs a bad build, up to an including build 5 (1.6.0_02-b05), of JRE 6u2, not just applet users. (I am merely posting this in the Applet forum, since I figured it was the most appropriate one.)
(For me, the issue manifested itself on both on both my home PC and work PC after installing it. IE would just crash, typically if a pop-up window or an external window tried to open.)
The fix is to use build 6 of JRE 6 Upgrade 2 (1.6.0_02-b06). This version is now the Sun download page (with the link explicitly labeled as build 6). However, since the bad build was publicly available for awhile, it will be in the wild.
To help you determine the version of any installation executables you may have already downloaded, here are the hash values for the build 6 windows installers: