I have had this exact same problem with my Whirlpool. Not sure if yours is a top loader like mine, but I found that slamming the lid would get it going. Then my husband discovered that there was a screw on the side of the lid that was loose. Not sure how a loose screw on the side of the lid prevents it from starting to agitate, but once he tightened it, the washer worked fine. No more lid slamming. Lol