How do i check and repair RAM memory?

recently i had a system crashed on my Acer 4520 laptop..
i tried everything but there was BSOD so i removed the RAM and tried to use.. it worked but still BSOD appeared..
if i insert either of the 2 RAMs it works but when i insert both ther is no Boot screen...
kindly help me
Sohail, May 2009


done
You might be adding to much RAM. Check your bios options.

Brandon, June 2009
link Click here to see other fixes for Acer.