I haven't had no negative issues to report on installing Windows 7 updates. The only thing that remotely consisted of an issue this week, was one of my computers (my desktop) rebooted an extra time to install the updates. No big deal to me.
I have 3 installs of Windows 7 64 bit, 2 Pro & 1 Ultimate (my desktop dual boots between Pro & Ultimate). Again, I repeat, no problems with updating.
Perhaps it's the users AV/IS programs giving the problems. Or has SP1 been installed? There's also another update that's required to accept future updates (KB976902) that needs to be installed, this may be the problem.
http://support.microsoft.com/kb/976902
If you're having trouble updating, make sure that this update is installed. Beware, if your system is non-genuine, there may be troubles afterward. This update cannot be removed.
Cat