IBM Thinkpad memory problems!

[Lespaul20]

I have a IBM Thinkpad A22M 2628-TTU.
The problem is I have three stick of memory for it and only one works.
I have tried all combos, here are the memory sticks.

Kingston
KTD-INSP75000/128
KVR133X648C3/256

IBM
20L0256 PC100

The first stick is the only one that works and it only works in one of the slots. My bios is up to date. The first stick I think is the one that came with it when I bought it and I bought the IBM stick shortly after and then it started having trouble reconizing it and now it doens't reconize anything but the KTD stick. I have run out of ideas except a bad M/B as the problem. Any help would be great.
LP20