Were is the clock battery in A compaq presario?

SOURCE: how do i replace the cmos battery in the

1. Place your laptop in such a way that the rear part is exposed.
2. Unscrew the locks of the covers to remove the covers and eventually expose your laptop's motherboard.
3. The battery is situated in the motherboard and it looks like a battery of a watch.
4. Remove the said battery and find a replacement of exactly the same kind and specification like 3.0V or something that is printed in the battery itself.
5. Then place the new battery and close the covers.
   

Testimonial: "thanks but where is the battery exatly I tried to do that locating of the battery. I found where my ram goes a wire attached to motherboard by red and black wires. and a round something covered in a hard black plastic am i supposed to cut plastic open and find battery there? the other panel i removed was where my hard drive was did not find anything there that resembled a battery so was i close/ let me know please can u all send me a pic of location of motherboard battery "