The problem is we don`t know what you (the Antivir) did that the icons changed back to XP?
There are two options:
1.) Refresh the icon cache: Download TweakUI (from Microsoft, right side), install it, at the bottom you have the option "REPAIR", chose repair icons (reboot) ...
2.) Systemfiles from Vista was replaced with XP files - then uninstall Bricopack in safemode (press F8 during bootprocess), install online all windows-update, then install the Bricopack again (in safemode).