In Windows 7, the Run dialog is actually located in Start > All Programs > Accessories.

Unfortunately the problem here seems to be a bug in Windows 7 where the Reminder notification is actually opening behind the Outlook window. One suggestion is to set your taskbar to not combine taskbar buttons. This can be done by right-clicking on an empty area of the taskbar and selecting Properties.

More info can be found here:
http://social.answers.microsoft.com/...&prof=required
No good permanent solutions yet, though.

-SW