Anyone else having problems? With application "windows" not openin

I seem to have a problem where at times I may click on for example, IE, WMP,
or even a buddy in YIM and the window for that particular application will
not open. I may try a number of times and it will still not open any more
programmes or applications, or windows of existing running programmes (extra
tabs on IE, windows on MSN)

What is the problem? Is this a common Vista bug?