According to Asus click here (& assuming I have the model right), the board supports upto DDR 800Mhz, but shouldn't really be a problem if you install 'faster' RAM.
I would try the CMOS reset first with the power cord unplugged.
If that fails, with the old RAM reinstalled, try setting the voltage manually to match the new Crucial's RAM voltage ratings, save settings & shut down soon after. You will be in effect over-volting the previous RAM, but only for a few seconds. Unplug power cord, replace RAM with new ones, reattach power cord & reboot.
Also, may be helpful if you could let us know the exact model number of the Crucial set. G