I tried to install windows 7 service pack 1 release candidate. it says I have prelease version installed, please install it first. I tried to look for kb976932, and install it. unistall is disabled. I tried uninstall from command line. wusa.exe /uninstall /kb:976932 it says service pack for microsoft windows (KB 976932) is required by your computer and cannot be uninstalled. what should I do ?