Eugene,
ArchiCAD was designed on a way that you can have as many AC versions installed as you would like to have. Those should work fine even running side-by-side.
It is good that you have already tested this with disabled Antivirus, usually such can cause similar problems.
Try to boot your Windows in safe mode and apply the hotfix then.
Let us know the result of that.
Marton Kiss
Chief Product Officer
GRAPHISOFT