This multi JRE issue is different from the other multi JRE issues reported against JDK7. As part of our multi JRE automated testsuite we install older versions of JRE from 1.4, 1.5 and 1.6 family and it has been noticed that once these older versions of JRE are removed new PLug-in under JRE7 fails to work with IE browser(with applets using applet tag)

Steps to reproduce:
1) Install JDK7 and then install 1.4.2_24 , 1.5.0_22 and 1.6.0_21
2) try to laod any applte using applet tag
Applet will get loaded fine using 1.7.0
3) Remove the older version of JREs leaving behind the 1.7.0 JRE only
4) now try to load the same applet again, it will either fail to load (plug-in/VM will not start ) or applet will get loaded using old Plugin
Same applet will work fine with Firefox