First up, boot from a MEMTEST86+ CD, and run tests on your RAM overnight. I'd expect a few issues, in which case RMA your RAM.
If you don't find any issues, it might be a case of incompatible RAM. Sure, you have bought RAM of the right spec, but it's not always as simple as that - though it ought to be! Often mobo manufacturers specifically approve particular brands/models of RAM - if you don't have such RAM you may find it difficult to get support from your mobo manufacturer. However, most will still help, so check out their support pages - perhaps they can help you out, or perhaps another buyer will have had problems with the same RAM.
Have you checked the mobo manual to check the spec and position of the RAM? Sometimes manufacturers insist that certain RAM configurations use particular positions or settings.
Failing that, sell your RAM and buy a different brand/model.
EDIT: I've owned plenty of ASUS kit before - they have some slow-but-well-marshalled forums - it's worth pitching your problem there, to find out if other people have had problems with your RAM or your configuration.