A word of caution, if you have
a number of BIOS to go through before reaching the latest version, you should update the BIOS gradually, i.e, updating from 0302>0406>0503>0602.
Pertaining to how you can update the BIOS,
download this app, install in compatibility mode(Right click installer>Compatibility tab>Windows Vista 32/64bit) and install the app by running as an Administrator.
Once the app is installed, run the app in Administrator mode and then follow through the instructions laid out in your manual, page 2-10.
If the system is running fine as is, then leave it as is.