Display problems like this are difficult to narrow down. Disabling hardware accelleration would force Astro to use software-based opengl rendering. That would let you know if its a video driver thing, or something more related to Astro's functionality.
You can also try changing your color depth/desktop resolutions (temporarily). People in the past have reported that sometimes 'blackout' problems like this go away when the deskop color depth is changed, and then changed back.
You can also check if there's an updated driver available for your video card. Sometimes downgrading also solves the problem.