There is an uninstall issue of JRE from 6u15,only reproducible with 32bit JRE uninstall.
To reproduce this issue by the following procedure on Windows/x86
   1. Install JRE on Windows XP/vista/7;
   2. Open "Java Control Panel" in Windows "Control Panel";
   3. Uninstall JRE with the "Java Control Panel" running (Java in using);
   4. "File In Use" dialog pop up and click the button "Ignore";
   5. Another dialog "Close Programs" prompt that some programs are using Java.
      Click the button "Cancel";
   6. Then click "OK" to close all the dialogs.

 Now the JRE could not be uninstalled normally anymore (no java working) without
 any warning message.It doesn't work even I re-login or restart the machine.To uninstall
 the JRE successfully,I have to repeat step1 to step5 and click button "Close Programs
 and Continue" at step5. It is very difficult to uninstall Java for the users who
 had failed to uninstall Java when Java was in using before.