Aurora R8, CMOS battery replacement

Hello I am getting some flashing lights indicating ram not detected and also ram failure, though I have reseated my ram and no success.

First I want to try and see if I probably need a new CMOS, as recommended in another thread of mine by another user , considering I have had this PC almost 5 years that may be the case and it is the cheapest possible solution.

What kind of CMOS battery does this PC take? I accidentally just tossed it in the trash and cannot find it.