Unfortunately, I ran into the same problem with the latest GameEx (6.19) on my home theatre PC. It's running a (legal) version of Windows MCE2005 with all the latest updates, .NET 1.1 and 2.0, DirectX 9.0C and Media Player 10. No indications whatsoever of any problems with my Windows and/or .NET installation, except for this GameEx error. The system consists of an ASUS Pundit-R barebone, 2.8GHz P4 Prescott core with 800 MHz FSB, 512 MB DDR memory, etc. In spite of the onboard video and sound, I was expecting this system to be perfectly capable of running GameEx (MAME itself runs flawlessly). Here's the log file: 20:15:24.3 26-5-2006: GameEx: Version 6.19: Starting Log 20:15:24.3 26-5-2006: Operating System Platform: Win32NT 20:15:24.3 26-5-2006: Operating System Name: Windows XP 20:15:24.3 26-5-2006: Operating System Version: 5.1.2600 20:15:24.3 26-5-2006: ERROR: An error occured while checking for previous instance of GameEx 20:15:24.3 26-5-2006: This can be caused by a bad windows or .net framework install. 20:15:24.3 26-5-2006: GameEx will likely function incorrectly as it cannot check for running processes 20:15:24.3 26-5-2006: GameEx will now exit with errors Perhaps I should add that GameEx runs fine on my desktop system, and I really like it. But of course, I would prefer to run it on my HTPC in the living room... Any new insights regarding this issue, or an easier fix than a complete Windows reinstall???