I bought a Dell Inspiron 14 3878 laptop second hand but I cant get into the Bios because it has a password, I have tried to remove the button battery for 10 minutes from the motherboard but it is still there. Can someone tell me what pins I have to short on the motherboard to clear the CMOS or a service manual showing what to do? Thanks all.
You need to call Dell with verification of ownership of the system - the password is stored in EEPROM. Disconnecting power won't remove it - only the master password (which Dell will generate upon proof of ownership) will do that. If the seller of the system can't transfer it to your name, return the system for a refund of your purchase price (or add the cost of a mainboard to the price you paid).