I made a choice not to use Java Quick Start as I am happy for Java to fully load up on the occasions that it needs to. This is easily configurable in Windows using the Java control panel applet in the Advanced tab.
Unfortunately, each time a Java update is installed it reverts to the default setting of 'on'. I consider this to be a bug as the installer is not honoring the current installation's configuration.
I am using Windows XP sp3 and have just upgraded to Java 1.6.0_20. I have observed this behavior during several previous upgrades.