Your PC's CMOS keeps track of the following system settings:
DATE and TIME: The CMOS keeps track of the current date and time.
Hard Drive: The CMOS keeps track of the type of the PC's hard drive. Most hard drives have a drive type number which identifies your drive. If you can't find this number you will have to enter the specific hard drive statistics which include:
Check your PC manual, or the settings are usually written directly on your hard drive.
Floppy Drive: The CMOS allows you to pick different drive types. Make sure you pick the correct drive type for your floppy drives or they will not work correctly.
RAM: The CMOS will automatically count total amount of RAM. If you add RAM you may have to run the BIOS setup program confirm the new RAM and save the settings.
Monitor: Some CMOS chips require specific monitor setting information. Generally your choice is monochrome or color.
Math Coprocessor: Some CMOS chips require this information, others recognize it automatically
That is a lot of settings! Don't worry, your PC should remember most of them.