The Asus Video 2.0 ASVX codec is currently only supported by their Windows 9x capture software. Graham Inggs provides the following information allowing you to play these files back on a Win 2K machine.
"ASVX - Form of Asus Video 2.0 where the audio is in the .avi file, but the video is in a .asv file. Currently only the Win9x capture software can make these files, but I have managed to get Windows 2000 to play them by copying the Win9x version of ASUSASV2.DLL, inserting the following string value into the registry:HKLM\SOFTWARE\Microsoft\Windows NT\Current Version\Drivers32 vidc.asvx = asusasv2.dll
and adding the following lines to the SYSTEM.INI:[Asuscap.drv] ASVX=1 ASVX_PLAYBACK=g:\ ASVX_OUT=g:\
Where G: is the drive on which the .asv files can be found."