Quick and stupid mistake, window manager

Hey guys, I'm currently in work and will be for the day (non computer work so i will only be in front of a comp for a few minutes and don't have time to google/search)

I just installed compiz on a friends comp (who is leaving the country in a few hours) and I messed up. I did a gtk-window-decorator --replace on xubuntu and now when i log in there are no window decorations :)

Basically how do i set it back to xubuntu default ? (not compiz)

Thanks.

if compiz is still running you should probably kill it.
if not simply press alt+f2 and run "xfwm4". usually this should bring back xfce's windowmanager and decorator.