Actually, I also had a problem with Stardock Central. After I uninstalled the 811493 MS critical update, SDC would no longer work. I had to uninstall SDC and delete the directory, then reinstall SDC to get it to work again.
The people over at SETI@home are experiencing a "slowdown" of their work unit processing after they security update to their software. The reason for the update was:
"Version 3.08 is a precautionary security release. There was a potential buffer overrun in the networking code of the client that is fixed with version 3.08. Note that to exploit this vulnerability, a potential attacker would have to trick the client into contacting a fake server rather than the actual SETI@home server."
As someone else noted, turning off their visus scanner clears up the slowdown problem (at least it does in my case, using McAfee). Strongly suspect these issues are all related.