Windows 7 - Blank dialog window during pgm install

Under Windows 7 Ultimate (64b), I've had issues during a program install where a window is open asking for acceptance of their EUL - but it is blank, and since you can't respond, the install has to be aborted.

This same issue has come up trying to run Corel Painter 11: When it starts, it throws up a helper window which is blank, and even worse, Painter gets all squirrely with the swirling 'busy' cursor... and you have to go to Task Manger to kill off it's process to get out.

What I've found is, this appears to be related to the logged on user. First I logged in as the built-in Admin, and succeeded in doing installs that didn't work before, and also Painter 11 ran fine. Next I tried creating a new user, also with admin rights (my normal user is also admin) and when logged in with this new user, the dialog window works and Painter 11 correctly.

So - my big question is - can anybody comment on what aspects of a user would cause this dialog window to behave so badly - for almost any prog that uses it.

Is my only solution to create a new user, and dump the munged-up one?

TIA!

=Alan R