Short desc:
 On Windows ( checked on Wista, XP Home, Win7 ) JavaUpadate disabling/enabling
 leads to changing path to jusched.exe
from correct "C:\Program Files\Common Files\Java\Java Update\jusched.exe"
to incorrect "C:\Program Files\Java\jre6\bin\jusched.exe"

As results JavaUpdate doesn't work after this.

This happens because since 6u18 b04 JavaUpdate *.exe files including jusched.exe are stored in C:\Program Files\Common Files\Java\Java Update and aren't available from
$JRE_HOME/bin.

See comments for details.