Win XP Security Policys

Any help would be good. I’ve just started at a new company and have been replacing the old pcs for new ones. My problem is one the older pcs that is now removed from the network has had all its user accounts apart from local admin removed from it.
Now when i log on to it i can’t delete some if the icons on the desktop + start menu. I also can’t access management console or local security policy or any other admin tools.
Any idea’s what might be causing this and how i can deal with it.
Cheers