Having Major Problem With XP Professiona

I can’t access any of my applications, I used my
administrator account in order to permit all other users (non-administrative) to access “Warcraft 3” – since administrative rights are needed to run applications. Not only is the game inaccessible,all other applications and
admin tools are inaccessible, and this is from every accounts including the administrator. I can’t even access the administrative tools to undo the change. I forgot what I used, it was either ‘Management Console’ in the Administrative tools or the group policy snap-in. I accessed it through the help screen. I enabled the option and then added the program to list of
allowable programs. I really don’t know how to rectify this, anyone have advice?