I uninstalled an application, lets call it
BigApp,
then cleaned up the registry using Regedit, removing all ocurrances of the app name, the company name etc.
Then I ran Regclean, as I always do after changing the registry (I'm not sure why).
Then I searched through the registry again,
and found no occurances of BigApp.
But when I edited user.dat, I found BigApp in there. Arent the registry and user.dat and system.dat supposed to be the same?
I know that they might differ for a short time, but after a few boots, shouldnt they be in sync?

Thanks.