Gateway One Long Beep

HELLP! PC Gurus! My laptop is a long beep, sometimes, Random .. What is wrong with him?!?

I have a Gateway 450XL laptop. This is relatively new. Was recently BEEPING at random moments. This was one long beep and it disappears, it does so at random moments. Nothing happens after the beeps, im wondering if the computer is telling me that something is wrong. I reformatted and installed Windows XP Pro on the computer three times, and I still can not get rid the beep. People of technology has arrived and replaced the motherboard, CPU and fan, the BEEP is still there! It is the mother thats sound.

Sounds as a stick of RAM at fault …. or possibly lose a card or defective … Anyway … he must be caught on security … if they only replaced the motherboard and cpu fan and not the RAM … thats where I would start my troubleshooting