Hi. I have now applied hotfix 89 and the problem remains the same. I also tried windowed mode with graphics set to minimum but this did not solve the problem. But, in windowed mode I can exit the program without resorting to the task manager. Thanks.
OS: Windows 7, CPU: I-7 960, RAM: 12 Gigabytes, VIDEO: Radeon HD 6950 with 1 Gigabyte, DRIVE: SAMSUNG 512 Gigabyte SSD