I need to perform a hard reset. How do I detach the battery?

My cintiq (dth w1310) won't boot up the loading screen any longer. Although it shows up as a secondary monitor and sound device when connected to my stationary. This suggests that it still sort of works, and various guides suggests a hard reset to give the cintiq a new chance to boot. We've opened up the cintiq to try and locate the CMOS battery to completely drain it. But we're stuck. Are you supposed to detach the cables to the big battery, or can we locate the CMOS elsewhere? And how do we proceed to do so? Is there a video guide to follow and mimic?

If its possible then I can present a picture of the process, if required.

Any and all feedback is greatly appreciated!