Got it working. I loaded the BMD Drivers, uninstalled my Vegas 10, which was on the machine, upgraded RAM from 4 to 16 Gb, cleaned my discs and caches. Vegas would play my mjpg files for about 10 seconds then crash, but an error message from my AMD Fire Pro graphics card would flash just after the crash. Snooped around Creative Cow and found several comments where the solution for timeline playing crashes was to turn off GPU Acceleration in Preferences>Video. I did this and it plays smooth as silk. The smoothest playback and sharpest picture I’ve ever experienced from Vegas. This is a new install on a new machine (64bit) for me, and I’ve used Vegas for 10 years. This is the first time it actually looks great without pre-rendering. Finally have the right hardware-software combo. Hope this experience helps others.