Hello.  
 
I'm planning on building a new PC and I have selected the ASUS P5K-VM motherboard and the C2D E8400 processor.  
I'm wondering... if the motherboard doesn't have the correct bios that supports the new 45nm processors, will it still turn on so I could update the bios?
 
Thanks.

It might but if not, you'll need to borrow a CPU.  I'd get a floppy and flash off that

Asus has the option to flash off USB.  
 
If i flash the bios using the floppy, do I still need to borrow a cpu?

 
From what I've read you can flash some BIOS even though the the updated BIOS is needed to run the CPU but not sure about that board.  You could send an E Mail to ASUS but don't know what kind of response you'll get.  Check the ASUS forum, should be something on there.  The reason I suggested the floppy is that they are always recognized and always work but I'm in the rapidly dwindling minority that still believes in floppies.  They're $7, don't take up resources, and don't detract from the appearance.

Ya if the board Bios don't support 45nm you will need a 65nm processor to boot to, so you can flash.

Go to their website lookup your board and check the supported cpu's for that board.
It does say on there site to update to the latest bios for 45nm CPU.

Yes, if the motherboard was manufactured with an older BIOS
that does not recognize the E8000 series CPUs, you'll need
to install a CPU that is compatible with that older BIOS,
in order to flash the latest BIOS that will support an E8000 CPU.
 
We recommend a cheap Celeron 420, if you don't have
another compatible CPU among your spare parts.
 
If you're not comfortable flashing the BIOS from a
floppy or USB drive, the ASUS Update software
can be installed from the Support CD after you
install Windows:  then, simply run the ASUS Update
program by navigating to Start | Programs etc.
 
The User Manual should have instructions for
launching and running ASUS Update:
you simply point it to the .ROM file  
where that file is stored in your file system, e.g.
 
C:\asus\bios
 
That's a good place to store such BIOS updates,
so that those files will be archived in any drive image
file you may prepare of your C: system partition,
using programs like Symantec's GHOST.
 
 
Piece o' cake, really.
 
Don't forget to download the latest BIOS for that motherboard
from the ASUS website.  It will probably be in a compressed
.zip file, so you'll need to run software that can decompress  
that .zip file e.g. WinZip or comparable decompression program.
 
 
Sincerely yours,
/s/ Paul Andrew Mitchell
Webmaster, Supreme Law Library
http://www.supremelaw.org/