Desktop Slowdown Over Past 3 Days

Over the past few days, as we've worked through this, the computer definitely got faster. It probably made the biggest impovement the first day, when we turned off all the redundant anti-spyware programs. After this last step to fix Security Center, when I rebooted, the machine came up with the New Hardware Wizard, but was unable to identify whatever the "new hardware" is. I, too, was unable to identify what it thought was new (so far!!). I'm nervous to see what doesn't work! It does seem pretty good now, though!

Good you got the improvements, and looking like you corrected the Security Center glitch as well. Reboot fully two more times then post back if the hardware wizard is still prompting there.