BIOS Problem

Hello,
I have an problem will my computer,
when i Start the Computer Computer says BIOS setting Wrong, Date & time not Confirmed,
How to Confirm that?
& second thing is that i skip this process by Pressing F2
then my system start loading for a longer period of time. I have to Restart the System then again same happens
& some time before loading Blue screen comes & system start disk check at this time system checks each & every disk

I tried to start system in safe mode, but system not started
some time if i keep system shut down for the Day then i start normally but after starting system hangs

Please Help
Regards
Rajesh