I have Windows 7 with Windows Live V 2011 (Build 15.4.3502.0922)

I pieced together a video a few days ago, saved it to my computer, then published on youtube with no problems at all.  I started a new project last night, finished it, and saved it.  When I played the saved wmv file, the screen went black in some portions of the 4.11 minute video.  I went back to Windows Live and re-saved it.  The wmv went black in different portions of the video.  I have tried re-saving several times, and every time, it is black in some spots, but it is never the same!

I have checked that my driver is updated (ATI Mobility Radeon HD 4250) twice.  I have done an error check on my drives.  I don't know what else to do.  I have read some of the threads and I can't follow some of the advice with more technical things.  Help?