If it mentioned "physical memory" then open the laptop and take out one of the RAM cards, see if it will boot.
That is assuming you have two RAM cards.
If it still doesn't boot, put the RAM card back in and take out the other one, try to boot.
Let us know if this worked.
Also, as Lemur suggested, download memtest86+ and put it on a CD/DVD or USB memory stick.
Boot to it and run it for at least 7 full passes.
This tests without your Windows OS running, it will also tell us if it's RAM - other hardware or the OS that is causing the crashes. RAM - Test with Memtest86+