If the original installer was competent, the countertop should be held down with dabs of silicone. It will peel up if you start at an outside corner. Use pry bars to work it loose from the sub board. You can put denatured alcohol in a spray bottle and spritz some underneath. That will help the silicone release. Driving wood shims underneath can also be helpful.
Jim Heaphy
www.TopRepair.com
Jim Heaphy
October 2007