Resetting Bios to defaults via removing battery and shorting terminals.

Hi

I read previously that one should replace the battery with a new one.
Is this necesary? If so, where do I get one? Anything I should take
precautions with when doing this? Do all boards (my one ga-k8n-sli)
reset to default. What happens if it wipes it?

Nasty Bios/Boot virus plagueing my system. Flash,new partions with
fdisk,format didnt work.

Thanks.