You should be able to change the sort order when searching using keywords, and you should be able to set your default sort order using the Customize menu in the upper right where you can switch between List or Gallery view.
If that is not working for you, try another browser to see if that allows you to change your sort order or your default sort order. If that works better, try clearing your eBay cookies manually in the original browser, and make sure that you are using the latest version of that browser, and try again.