The ASUS website should have an updated manual with the required info. I wounld't assume all is well with the single beep since every manufacturer has different standards. Does the system boot...

Try running memtest +86 to see if the memory works. If so it is probably a hd issue.

Pull the battery out and leave it unplugged for a few minutes. After that, plug it back into the AC adapter and try to power it up.

Try reinstalling Windows over the current copy. Once that comes up you should be able to back up your data, format the drive, and install a clean Windows environment.

are all the cartridges secure? Have you left it unplugged for a day or so and then tried it again?

Sounds like you've troubleshot it pretty thoroughly. It's got to be a bad MB.

Disconnect the power cord and pull the battery out. Let it sit for a few minutes and then reconnect the power. If that doesn't do it, strip it down as far as you can go. remove the hard drive, cdrom...

This could be either a hard drive problem or a power supply problem. I suggest you try another hard drive in the system to better isolate the problem. Just connect the power though, if you boot...