There is a new BIOS for M2N-SLI, available on ASUS FTP server -
BIOS 0402 (07/13/2006). You can either download it from the link above or thru Asus Update. I wonder why they kept it out for the whole month before putting up for a download... Anyway, let's see what's new and hope for a fix regarding restarting issues :)
UPDATE: BIOS flashed! I have not noticed anything new in BIOS. All devices have been re-installed upon logon to Windows, so there must have been a change with ACPI, I think. Restarting issue is still there, which kind of leads me to believe that maybe it's not the BIOS but something about nForce570 SLI chipset drivers that cause that? :shrug: