Thanks for your quick reply!
I tried both. but no luck.
In the case of killing svchost.exe - with the first one I killed, the message came up that windows is shutting down, as that process is needed for it to run.
In Safe mode, I couldn't get the update started. After the microsoft process was done checking my computer for updates, it displayed a message saying that the page could not be displayed because an error was encountered.
I am guessing that I have a virus that prevents me from getting this update, and I have posted the hijackthis log file in the appropriate forum. But I am not sure what needs to be resolved first - the virus(s) or SP2 update?