PC won't boot with new RAM

[Skyrme]

Hi, I just bought 2 sticks of "Kingston 2Gb Ddr2 667 5300 Desktop Pc Ram D25664F50", but after adding them to my system my compute blue screens and won't boot.
According to the crucial memory scanner, this is what's compatible;
"Module Size: 4GB kit (2GBx2)
Package: 240-pin DIMM
Feature: DDR2 PC2-5300
Specs: DDR2 PC2-5300 • CL=5 • Unbuffered • NON-ECC • DDR2-667 • 1.8V • 256Meg x 64 •"
Anyone have any ideas why it won't work? I have tried starting the PC with the new 4GB of RAM on its own, as well as with 2 1GB sticks that I already had in the PC.

Thanks

 

[Ahmadjon]

What memory bus had your old RAM?

 

[Skyrme]

667