I've had an ongoing issue lately when doing some browser compatibility work in IE8.  Pressing F12, or activating IE Developer Tools from the Tools menu loaded a window, however the window was empty.  Clicking on the window in the Windows 7 taskbar, had no effect.  At first, I thought that something had become corrupted with my IE8 installation, so I uninstalled IE8, cleaned my registry, and reinstalled it.  Pressing F12 after the reinstall yielded the same behavior.  I reset Internet Explorer 8 from the Internet Options Window.  Still a no go.  Having almost resigned myself to not having IE8 Developer Tools, I decided to check again on Google to see in anyone else was having a similar issue.

I happened upon a post at http://social.answers.microsoft.com/Forums/en-US/InternetExplorer/thread/92642a56-9a10-4704-b6b3-0977cc005b73 where the author was having a similar issue and actually provided a step in the right direction to solving it.  In the post, the author figured out that somehow the developer tools application had moved off his main screen (he was using 2 monitors) and was located on the second monitor, except was resized.  Using this tid-bit of information, I decided to see if my issue was related.  Now, I was only using a single monitor (my laptop monitor) so I couldn't figure how the application might have jumped off the screen.  Interestingly enough, it turn out that my IE8 Developer Tools had done the excat same thing.  Realizing this, I simply used alt-tab to activate the Windows 7 "active" window to highlight the IE8 Developer Tools, then clicked ctrl-right arrow to find my lost screen, then by clicking move I was able to drag my IE8 Developer Tools application back into my main window.

Problem solved.