Power loop on satellite a100

Recently I started to restore my first laptop, toshiba satellite a100-220(for those will say why I chosed a105 is because I didn't find a100) so I tried to power the laptop on and it powered and turned off automatically and after powered and turned off again. I disassembled the entire laptop I checked every part (cpu,ram,hdd,lcd,modem,odd) I replaced power jack with another toshiba power jack I used 2 toshiba chargers but no results. I can't find the bios battery and it exist a method to reset bios but this require the "square" of the WiFi board(this version didn't have built-in WiFi and also the slot is missing), I didn't flashed any custom bios (I never updated the bios on that).When connect the charger the charging led goes on and also the battery is dead. That laptop have a celeron m380 1.6Ghz cpu (Dothan PGA479), 2 GB of ram (256 mb stock), 80 GB HDD and 128mb vram ATI gpu. PLEASE HELP ME!