Hello @edwinfu,
Thanks for writing in!
You are experiencing the issue because after installing WooCommerce, you did not clear the cache and regenerated the minified html, js and css files. I have temporarily deactivated the W3 Total Cache plugin and now the product page is displaying correctly. Most of time, caching plugins can cause the changes to not take place on the front end. It will eventually show up when the cache regenerates, but it’s not ideal if you’re looking to see your changes immediately. Caching plugins are best to turn on only when you’ve finished building the site.
Check your site now.