Dear Redker, I noticed from your dxdiag.txt file that you have a system configuration that coincidetally happens to be one that get many reports about. Basically, the red flag seems to be "Dell Optiplex running Windows 7 with an ATI Radeon Graphics card". A quick fix usually is to replace the ATI Radeon card with ANYTHING else (e.g., nVidia). It's just some kind of hardware/software interaction. However, there have been cases where other solutions have been found. Or other causes I should say. Do the sample run slowly on this same system? e.g., especially the "image priming" sample and the "IAT" sample? The image priming sample in particular is a good one to start with as a test. If it runs fine, then we can look at the differences between it and your study. But if it also runs slowly, then it may simply be an issue of display hardware, or associated drivers (which can also be the cause--e.g., too old, or too new/untested).