If Windows repair didn't sort it, it means you need to reinstall Windows.
E: Wait...My Windows 7 install doesn't have any of those dll's. It's more than likely not a Windows problem, but a problem with a program. Go through your process list (Ctrl+Shift+Esc), and kill each one that look like it shouldn't be there (you should know what I mean by that, i.e., don't go killing essential Windows processes), until those message boxes disappear. If they don't disappear, start killing the processes left behind. Make a note of the name of each one (on paper...) as you're doing it, so if Windows crashes you'll know which one not to do again. This should tell you which program is causing the popups, which will let you find it and destroy it.