A. If your BIOS is not holding custom settings, it's probably time to change the CMOS battery. A good indication (although not the only one) that your CMOS battery has died is that the computer will not retain the correct date and time.
B. Most BIOSes have an option to turn off floppy drive detection at boot-up and/or disable the floppy drive entirely. Systems usually will barf errors if the floppy is enabled in the BIOS but no floppy drive is installed.
Given that you say the BIOS is constantly reverting to default settings, problem B is most likely related to problem A. A new CMOS battery only cost a few bucks; try replacing that first and see what happens.