Problem with Satelite M500 cant start at all

Question

1st question, how to get the specific model no like mine m500 -xxxx where to find the xxx part?
2nd problem, i have this satelite m500, it works normally like all other laptop, but there's this problem where it randomly happen. It works well in the morning but after i shut down it for some hours, i cant start it anymore. After i press the power button, wat i see is media button light is on, mouse pad light is on, but the screen didnt start up, is like u start up the "light" of the laptop but the inner part is not running at all.
It happen a few times to me before, for those previous case, i jus keep on on and off till it works normally. for now, its not working for more than 12hour.. not sure whats the  main problem. i've check on the ram, its not loosen and it seems working because i can feel the heat.
please help..

Answer 1

1) Try starting it without the battery in.
2) Try starting it on the battery only, without the AC
3) Power it off, unplug the AC, remove the battery:
    i) then remove the RAM modules,
   ii) next replace 1 RAM module in a different slot
  iii) replace battery and AC
   iv) try to restart
    v) repeat i-iv till you get it to start, or you have tried each RAM module in each slot
If you can get it to start with one of these methods, and Windows seems stable running that way, then flash update your BIOS following all the directions. But, you should NOT update the BIOS without the AC plugged in.
If it starts properly after the update, power off, replace everything, and try to power it on again.
Good luck
Mike