|The bios will NOT retain the current date and time after the computer has been shut off|
- if the cmos battery on the mboard is too weak or dead.
Most Cmos batteries are okay for up to 5 years or so.
- if the cmos battery was installed backwards in it's socket - the + on the top surface of the battery should be showing where you can see it when the battery is installed
- rarely - if the metal contact that is supposed to touch the + side of the battery is bent away from the battery - remove the battery, bend the contact towards the bottom of the battery socket, install the battery.
- rarely - if there is corrosion on the metal in the battery socket - it can usually be cleaned up easily with a bit of household vinegar on something such as a Q-tip - don't forget to clean the under side of the contact that touches the + side of the battery - clean up any excess liquid - the metal surfaces must be dry when you install the battery.
- possibly - (the battery is good and being recognized fine) if you have moved the clear cmos jumper on the mboard to the "clear" position but forgot to return it to the "normal" or "run" position.