Take apart an optical mouse

Step 2 Find and Remove the Screws.

A lot of "consumer" products with "no user serviceable parts inside" will hide their screws, both to discourage dis-assembly, and to make the product look better. In this case, there are four screws hidden underneath the little teflon "slider" pads on the bottom of the mouse. The pads can be pried off with a knife or small screwdriver, exposing normal philips head screws.