Audio alerts are not any software problem but the bios pointing to a hardware problem at post time. Once the battery was replaced did you leave everything at the factory defaults or see the settings changed to the way you had them before like OS2 support enabled, PnP yes, and so forth?
If you originally had to enter dram timings manually were those re-entered? When arriving at the Asus specifications and seeing that the board there sees an AMI not Award bios the beep code points at: "1 long, 3 short Memory test failure A fault has been detected in memory above 64KB" according to bioscentral.com.
If memtest reported no errors with the dimms tried all on one slot try one by itself on another to see any of the other dimm slots are bad. Specifications are seen at ASUSTeK Computer Inc.