I can't find an ASUS A7VBX-MX but there is an ASUS A7V
8X-MX and it's drivers are
here. There are some ASUS A7VBX-?? motherboards but they appear to be OEM motherboards and don't have drivers supplied by ASUS. In that case, you should run
Everest and get the internal info about your motherboard. Just find the retail version of the motherboard which is closest to your motherboard. It's probably very similar to the A7V8X-MX. You can probably use its audio driver and the video driver can be downloaded straight from the company which made the chipset (probably a VIA KM400).