Help with X205 crashes and bios beeps

Got a new X205-SLi5 last month. The 2nd night i had it, it began to randomly crash after being turned on for just a few minutes. Screen would go black, sound (if any was playing) would repeat real fast then turn off..like any other crash. When i try to reboot it, the screen does not turn on and i get a beep from the BIOS, just a single long beep every 3-4 seconds. It will continue to do this unless i leave the lapto turned off for 3-4 minutes first, then it will turn on and boot back into windows...only to crash again a few mintues later.
I have called toshiba and they sent my to a local repair shop to get warrantly work done. The shop was unable to determine what the problem was, though they did order and replace the mobo and video board. Yet even after that and 2 reformats with the recovery disks i am still getting the same problem. Called toshiba and they said I will have to send the laptop end to get it checked (still unable to determine what could possibly be the problem). i would really like to avoid losing my laptop again if possible. Can anyone tell me what they think is going on, as well as what the beep code means? I saw some old posts saying to check the RAM, whch i would if i had a screw driver on me right now to get the plate open,so will check that when i can.