Problems after installing Malicious Software Removal Tool

Archived from groups: microsoft.public.windowsxp.security_admin (More info?)

Windows update installed the May version of the tool and since then strange
things have been happening. If I single-click on a desktop icon, it brings up
the menu that has open on the top, double clicking does no good at all and if
I right click nothing happens. For instance, even from the start menu, if I
click Run, it brings up a little box that says run and I have to click that
button. If I click on Internet Explorer on the desktop, I get the menu--if I
click on the bottom toolbar, it opens right up. I have checked the mouse
settings, the folder options settings, I have tried to system restore to
before Friday, all to no avail. Any suggestions as to how I can get back the
ability to double click to open and to right click at all?