I recently replaced the keyboard on my ThinkPad, as some keys had stopped working and I figured the most likely reason was dirt or maybe even moisture that got into the keyboard over time. To my surprise, with the new keyboard, exactly the opposite set of keys work, but the remaining ones which worked before do not. So, now I have two keyboards in which only complementary, but non-overlapping, subsets of keys work (each keyboard only has about half of the keys working, which make this problem particularly annoying). Has anybody ever observed such behavior on a laptop? I assume it must be some problem with the connector on the motherboard, but I still do not understand how opposite sets of keys could work on different keyboards (specially as one of them is brand new).