The first hit is http://support.gateway.com/s/Mobile/Gateway/6000Series/5386nv.shtml
Two clicks and I get disassembly manuals. The battery is not easy to spot but it's the MA2A model like you find on Amazon or Ebay.
Remember this is one of those Pentium 4 Socket 478 based laptops so these have a bad history. Feel free to vent about it but to fix most I find I have to get a new mainboard.
I woke up yesterday with no computer. No sound, the battery is good all the lights come on but there is nothing on the screen no boot screen no xp nothing. Recently my wireless mouse went dead & I believed it to be the mouse (today I hooked it up elsewhere it works like new) the clock on the laptop has also be wrong most recenlty. I supsect it is the cmos battery; however I opened up the bay for memory and did not see a cmos battery (it is the largest compartment on the laptop) there also is nothing in the user guide to tell me where the cmos battery would be held. I would like to try to replace it first as I have eliminated it being the 1.) Monitor (hooked up an external monitor with no luck.) 2.) the battery (i replaced with new with no luck.)
Does anyone know where the cmos battery might be held?