Normally there is a black piece of plastic that is underneath the memory modules. You will need to lift away that plastic and look for 2 solder points. They kind;ve resemble 0 | 0. the two O's are the solder points and the | ist just a line drawn between them in white stencil. With the battery out, and the laptop unplugged, link those two solder points with a paper clip or conductive screwdriver then turn on the computer. This can be really tricky and easiest to do if the laptop is turned on it's side. Let it boot for about 10 seconds, remove the connection to the solderpoints, and turn off the computer. Then try rebooting and your BIOS should be clear.
I see a contact point under the memory module, can I perform this procedure without the memory modules installed?
Yes, that's the only way to do it. Sorry, should have mentioned that.