Desktop Hardware and Upgrade Questions

Hi there! I'm trying to see if I can get some advice for properly flashing the BIOS on the computer that I recently got my hands on.  Essentially, I have been building a PC out of components that I got off a decomissioned dc7700 cmt PC from my University, and what I did was take the motherboard and its CPU (Intel Pentium D, I belive it's the 945 at 3.4 GHz), and get a new PSU, a PC case from a friend, and a new Hard Drive.  I installed Windows 10 64 bit on the fresh HDD, and as it sits, the computer has 1GB of DDR2 RAM (RAM Sticks I bought haven't arrived yet).  Currently, the BIOS version on it is the Hewlett-Packard 786E1 v01.05 8/30/2006.  I want to upgrade to the latest BIOS available for this computer, so that I can swap out the Processor for a more advanced Core 2 Duo in the future, and so that it can recognized the RAM amount that I install without any problems (8GB in total).  I checked the softpaq method, but there isn't a softpaq for Windows 10 for this old of a machine.  I also wanna make sure that the Motherboard doesn't get bricked, because that would be the end of my PC dreams T_T.  In any case, I'll appreciate all the help I can get.  Thanks in advance.