I would be stoked if they'd rely implemented "security" and have the pwd in non volatily storage. How long have you removed all power sources (PSU + cmos bat)? It can be that still some caps on the board hold up the power enough if you do not wait long enough.
It is important to understand that clearing the CMOS will: -Restore BIOS's default settings.
It is important to understand that clearing the CMOS will not: -Restore the original BIOS code (will not revert back to the original bios version).
Old CMOS clearing method *
Step 1: Disconnect the main AC power by either shutting off the power button on the back of your power supply or simply pulling out the power cable.
Step2: Wait a minute to be sure all the capacitors and coils have discharged. To be really safe you can press the power button which will drain the capacitors for sure.
Step3: Move the CMOS jumper to the clear position, this is usually done on MSI boards by moving JBAT1 from it's original 1-2 position to 2-3 position as demonstrated in the photo below. If you are not sure or have a non MSI board you must find the correct jumper in your motherboard manual.
*Note to all nForce2 users, your board usually has a special "safe mode" jumper for the FSB. You should also set it to the safe setting in case you have been overclocking since the normal clear CMOS jumper will not reset the frequency settings on these boards. You may refer to your user manual.
Step4: Wait a minute to be sure the CMOS has been cleared.
Step 5: Return the CMOS jumper to it's original position.
Step6: Restore power to the system.
which I assume is what you did so far... that does not sound great
Normaly if you unplug the system from the wall, and then take out the bios battery for a few minutes. Then it basicly should reset the bios to factory default. Unless the bios password is hard stored on an additional chip.
I´m currently looking for any information if there is an additional chip on it or not. But it doesnt sound very likely. I would atleast recommend to contact Msi for now.
In the mean while we might look arround if we can find some method to fix this. It would ofc be rediculous if you loose your bios password, that you are unable to reset it back to factory defaults. Allthought "if im right", there is an option in the bios, that exaly says "password clear" and if that option is set to disabled. The bios password will indeed not be cleared after Cmos reset. I think that were your problem sits.
Does the G45 Gaming has dual bios? Edit: nope its single bios.