Page faults in win2000

Hi, When adding more memory to my Fujitsu-Simens Scenic S, OS is Windows 2000 sp2.
I have 128 MB and are adding 128 MB more, memory modules are the exact same. They works just fine when using just one of them!! But 2 together – not!
I’ve replaced the motherboard but didn’t help.
I get Page Fault in nonpaged area.
Following error codes show up on the BSOD:
0x00000050, 0xFCDB9030, 0x804B0BE0, 0x00000000 at adress 804BB0BE0 base at 8040000

Antyone can help me out?
regards

//Hakan