ultraviolence

Hi, I have an Acer Aspire M5201 running Vista Ultimate. Recently I've been noticing a continuous beep coming from the internal speaker whenever the computer is turned on. I know that there are different reasons for beeps and I've looked online for the code of a continuous one but cant find anything. I've heard it can be to do with RAM not being inserted properly but I've checked that and its all fine. Can anyone tell me if its an alarm for overheating etc (and how to turn it off in the American Megatrends BIOS if its possible, I had a look but couldnt see anything) or an error code? Thanks.