The suggested secedit method will only reset security settings to default: NTFS, registry en services permissions, user privileges - basically everything under the Security node in GPEdit. This won't affect any user interface restrictions, which are all registry-based settings, located under the Administrative Templates node. By the way: even if the restrictions were applied by editing the registry directly, they should still show up in GPEdit. After all it's the same registry entries, whether you change them in GPEdit or in RegEdit.