Win DVD Creator problems

I am using WinDVD creator to capture VHS to burn to dvd. Sometimes the tape I am copying looks great when playing on my TV but the video in the Win DVD Creator preview window looks wobbly and shaky and this is how it records. This has happened maybe 5 times out of 200. Does anyone know what is causing this and how to correct it? Thanks!

try defragging and turning off all background programs when capping