Hi, I had a similar problem - shaky videos which originally did not shake until my computer crashed and the Windows XP operating system was reinstalled. It appeared that I didn't have the codecs for MPEG-2 format videos.
After trying to download MPEG-2 codecs without success I found that my video editing software (Adobe Premiere 10) solved the problem - simply by editing the videos and exporting them back to the same video folder. The original videos still shake but the processed ones don't and appear entirely normal. http://img.tomshardware.com/forum/uk/icones/smilies/bounce.gif