Installing WSUS 3 sp2 is needed to support patching Win7 on your network.
To install, you'll see that you'll need to run through the install process by clicking next, next, next......... and importantly at the end...cancel.
Click to accept the install
When you click FINISH, there's a final important step
When the wizard begins, hit CANCEL, and your install will be done. It will pick up your existing settings and make no changes.
In past installs it might also look to the largest free drive, so just in case you may want to temp disable a large external usb drive just to be sure.
Don't forget (as I just did)
From: Dave Nickason FYI, when you install WSUS 3.0 SP2, you need to upgrade to the newest
version of the report viewer. I've installed both the SP and the viewer on
my SBS 2003 and my Vista workstation. Both installed easily and with no
reboot required. After the server install the configuration wizard starts -
just cancel it.
Microsoft Report Viewer Redistributable 2008