Here's the background: our company has one particular system that will only run properly using Java 5 update 11. Before recently, I simply used this version of Java for everything because it ran well enough. I run most things in Firefox or through Firefox using IE Tab, but occasionally I'll use IE itself, such as for this one system, because it tends to crash Firefox. (This computer is an HP laptop with Windows XP.)
Recently there was some sort of glitch with my install of Firefox that prevented any web access except local systems to run in native Firefox. Anything would run in IE tabs as usual, but not in native Firefox tabs. So I decided I had to upgrade Firefox from 3.0.whatever to 3.6.8, and that solved that problem. However, Firefox 3.6 and above will only recognize Java 6 and above.
So now I want to run Java 6 for Firefox and Java 5.11 for Internet Explorer, which will satisfy all requirements. The problem is that even when Java 5.11 is installed first, Java 6 overwrites it as the system version. Java 5 still exists as a user version, but Internet Explorer will no longer recognize that I have it installed. See screenshots of the User versions and the System versions tabs in the Java control panel settings, and the Java section of the advanced IE settings. This is with both versions installed. When I had only Java 5 installed, IE happily recognized it. The advanced setting said "Use JRE 1.5.0_11 for <applet> (requires restart)" instead of "Use JRE 1.6.0_21 for <applet> (requires restart)" as it does now.
How do I get Internet Explorer to use Java 5 instead of Java 6 while still allowing Firefox to use Java 6?