Who installed the IE7?

Tech-Archive recommends: Fix windows errors by optimizing your registry

Does anyone know how to tell how an update or rollup got installed on a
computer?
Our WSUS server has IE7 set to Declined but one of the workstations got
it installed anyway.
Does the manually run Windows Update create a log? If it uses the
Windowsupdate.log how can you search to find manually downloaded items?
Thanks

.