I would not reccomend flashing from windows, see if there is a .iso or .bin file, with the .iso file you simply burn it to a cd the restart go into bios settings and set defaults, save and exit, then during post choose to boot from cd. With the .bin file you put this on a floppy disc, and boot to floppy. There should also be a usb flash drive method, but that involves a little more. I would reccomend the cd method if they have a .iso file available.
One thing that many people forget to do after updating the BIOS is to clear the CMOS memory. Failure to do so can lead to unpredictable results. Why do you want to update the BIOS anyway? You should only update the BIOS if you have problems that an update will fix.
I believe with this motherboard that you use the BIOS utility to program a flash drive to boot before the operating system installs and you update the BIOS from it.
I heard that on occasion bios updates can lead to faster boot-up times, etc.
They can also cause you to have problems you never had before.
BIOS updates can help if the update was written to fix a specific hardware problem you are having.
But other than that, BIOS updates, the best advice out there is honestly this:""If it ain't broke, don't fix it"
If you do something wrong during the update, you will be left with a dead motherboard. The only way to fix it then is to buy a new BIOS chip from your board manufacturer, or send the board back them if the chip is not removable have them restore the BIOS for you.
But if you do have a problem or just want to do it to see how it works, the worst you might have to do is flash back to the version you have now, if you do the flash correctly.
Since you apparently did not take the time to read the update instructions online at your manufactures web site where you got the update, or read your manual, I certainly wouldn't attempt it myself at this point. Enlist the help of a friend who knows what they are doing.