Fix for the infamous GUIMiner interface not showing up...
I had the same problem that others have had with the interface not showing up (it appears in the task bar, but the window never materializes). The usual fix (using keyboard shortcuts to move the window) did not work. The window was not hidden or otherwise out of sight. It simply was not there. I figured out that the culprit is the AMD APP SDK v2.8 installation.
I have verified this on two completely separate systems (both Windows 7 x64 - but no other SW or HW similarities). I can fix the issue by uninstalling SDK v2.8 and installing v2.7. I can reproduce the problem by uninstalling v2.7 and re-installing v2.8.
I am guessing the program hangs before the window is created when it polls the 2.8 OpenCL SDK drivers for devices, etc... (Just a guess).
I don't know if this will help anyone else, but I wanted to share in case is does.
I have Win7 x64 box as well. I uninstalled SDK v2.8 and installed v2.7, but didn't have any success. The windows is not hidden. The icon is in the system tray, but if you hover on it with the mouse it quickly disappears. You also can't alt-tab to the application. Any other ideas? I'm running GUIminer as administrator.