I tried to upgrade Memory from 2 to 4 GB and got 2 x 2 GB PC2-5300/5400 DDR2 667MHz, which I put into the yellow slots, but it doesn't want to boot. It makes no noise and nothing appears on the screen. I flipped them and reseated them several times to no avail.

Weird enough, it works with one of those (doesn't matter which one and in which slot) and even in combination with one of my old Kingston KVR533D2N4/1G memory modules to give me 3 GB RAM.

Any idea, why it will not work with both 2 GB modules?

Kind regards,