Computer will not boot up consistently because of RAM

[MalikAlwan]

My Laptop which is a Toshiba Satelite A660 won't startup every time I press the power button. So I tried to reseat the RAM which worked for the first time, to make sure I turned my laptop off and tried to power it on again to no avail the laptop did not turn on. I tried reseating it but it did not work, i reseat another three times and on the third try it finally booted up. If anyone has any idea how to fix this please help!

 

[Lampda]

Run memtest86+ v5.01(download it for free here:http://www.afterdawn.com/software/system_tools/misc_system_tools/memtest86plus_iso.cfm)
Do 2-4 passes.If it doesnt show up any errors then maybe the ram slot is faulty