Bluescreen after changing RAM

[alien5555]

window 7 home premium 64 bit
add up new 4gb RAM

bluescreen start to occur after changing RAM..
why it happen?

 

[Maguscreed]

looks likely memory was sold damaged, or manufacturer error.

if you want to check the memory yourself. There are good instructions for that here:
http://www.sevenforums.com/tutorials/105647-ram-test-memtest86.html

You may be in a return situation with your new ram here.
Best to verify with the procedure linked above though.