I have a ThinkPad A22m 2628 PF1. I had 2-256mb installed for several months. A week ago my IBM started acting slow. I found it was showing only 256mb's These by the way are IBM memory. I found out the outer slot was not reading the 256mb
an switched in the old 128mb. in worked for about a day and quit. None of the memory boards work in it now, but do in the other slot.