It sounds like you're having trouble accessing the BIOS on your LOTUS13 BA75-03712C motherboard. Here are a few things you can try:
Check the boot sequence: Make sure that the boot sequence is set to boot from the hard drive first. This will give you more time to press the F2 key to enter the BIOS.
Check the keyboard: Make sure that the keyboard is connected properly and functioning correctly. Try using a different keyboard to see if that resolves the issue.
Check the CMOS jumper: Some motherboards have a CMOS jumper that can be used to reset the BIOS settings. Check your motherboard manual or the manufacturer's website to see if your motherboard has a CMOS jumper and how to use it.
Check the BIOS battery: Make sure that the BIOS battery is properly connected and functioning correctly. Try replacing the battery if you suspect it may be the issue.
Check the power supply: Make sure that the power supply is providing enough power to the motherboard.
Try to access bios with a different method: Some motherboards have a backup bios key, like Del, Esc or F10, try those keys to access the bios.
It's worth noting that all of this troubleshooting steps are suggestions and not a guarantee that it will solve the problem. If the problem persists after trying all the above steps, it may be best to contact the manufacturer or an authorized service center for further assistance.