Inspiron 9400 - Memory Parity Errors

For quite a few months now, my laptop suddenly flashes to a blue screen with text such as..

NMI: Parity check / Memory Parity Error.

After reading around on forums after the first few incidents, some said it was problematic RAM; and so, I bought Kingston 2 x 1GB RAM (replacing Dell 2 x 512 MB), arriving yesterday. However, while it is a performance upgrade, and all that goodness, I experienced another Blue screen, and the same message.

 

Does anybody know how this can be fixed? :)