You need to know the brand of bios installed. You should see this on the bootup(POST) screen. Hit the 'pause/break' key to stop it so you can read it if necessary and then <enter> to continue boot.
Here are a couple of sites with beep codes.
http://www.computerhope.com/beep.htm
http://www.bioscentral.com/beepcodes/awardbeep.htm