Access2000 freeze/disappearing help

Working to design subforms in Access2000 (novice developer). As I try this and that — and make errors of course — eventually, either Access itself freezes completely or the wizards and help functions disappear. I’ve been invoking the ExprBuilder as well. I haven’t been having any other problems w/Access to date; is this a peculiarity of the subform/wizards/ExprBuilder triumvirate?