How do I update my Phoenix bios now that I am using Windows 7?

Before I explain my dilemma let me say that I know i have an old cpu and motherboard, but I just need to keep it going for a bit longer.

Bios = Phoenix awards 6/2/2006
My current motherboard is an ecs c51gm-m am2 and the cpu is amd 64 x 2 3800+. I upgraded to Windows 7 and I didn't have any bios problems. According to the ecs documentation on their website the bios only supports up to windows xp amd 64 x 2.

I have an amd 64 x 2 6000+ am2 cpu lying around so I thought I could just swap out the cpu's, but before doing so I needed to update the bios. According to the documentation, the updated bios from 05/03/2008 would recognize the faster cpu. As far as os's were concerned windows 7 was not an option. So that's my dilemma. Am i just sol or is there a way to update the bios for windows 7?

If you must update the BIOS, I would use the DOS updater instead of Windows. see this

How to use flash utility

Just make sure that BEFORE you do the BIOS update, BOTH of the following are true:
1) You have way to save the current working BIOS to offline media such that it can be used later to restore the BIOS
2) You have a way of booting the machine, if the BIOS update fails, such that you can restore the former working BIOS.

The risk you run in doing any BIOS upgrade is that, if it goes wrong, you can end up with an "electric brick".