First of all, you need to identify the BIOS version you already have, and see if the "NM" version dated 7 January 2000 is a later version.
This BIOS update, does support drives larger than 40GB, and there are even more recent updates than that.
However, if you have never done a BIOS flash before, make sure you have all the required information to hand. This operation should not be taken lightly, and you can read many threads here about ruined motherboards that have had "flashes" go wrong.
Make absolutely sure you have the correct files AND you know exactly how to go about it. If not, seek help from someone who has carried out the procedure.
The BIOS files are available click here
and a tutorial click here