Windows 7 gets slower and slower, and then.......

When WU is set to manual under services WU won't run automatically when Win starts.
If WU is set to Never Check on WU page, when you manually run it, it will give you the available updates. Then you decide what updates you want to install. I now only install Security ONLY updates and the Office updates.
For security updates, have a look at my post MS releases SP2 for Windows 7 - Windows 7 Help Forums.
I add the Security ONLY updates link every month.

bill2reg said:

Chitownbob, not sure what the "viewer" is.

Event viewer is a Microsoft tool for viewing system events. START SEARCH event viewer.

You can drill for it yourself under All programs, Administrative tools.
I usually view Administrative Events under custom views. Any errors can be googled. Ignore errors. Don't get too freaked out by errors unless they are recent and consistent. Your goal is to see if there are errors occurring during startup that are not reasonable or might cause your error.