If none of the memory modules make the system POST, again, some sort of BIOS corruption must've taken place; hence, I'd recommend trying booting up the system without memory to see if the board beeps; if it does, then, proceed as follows:
1. Clear the CMOS as outlined here:
Note: Make sure you leave the battery out for 20 min.
Attempt to boot the system up (with the memory in).
2. If the problem continues, please, provide the following details:
2.1. Altered Assembly Number (AA #) of your board:
Note: The AA# is located on a white sticker, right on the board itself (see http://tinyurl.com/6j8nbf).
2.2. Make and part# of the testing memory modules:
2.3. Make and wattage of the power supply used during the tests: