Does dmesg show anything when a card is inserted or removed?

A few shots in the dark based upon past discussions in these fora:

• There were reports from several N810 owners that their SanDisk branded micro-mini SD adapters would not work in their N810s. The SanDisk adapters worked everywhere else, and the N810s would work with other, non-SanDisk adapters. The N810 and SanDisk adapters sometimes just don't get along. (SanDisk cards are fine.)
• A number of N810 owners who complained their memory cards never worked in their N810s later found they just hadn't inserted the cards far enough. This probably isn't you, but it did happen to many people.
• Opening the memory card door on the N810 activates a switch that leads to the OS attempting to unmount the card. If that switch (or the card door itself) is damaged, the OS may never be getting the all clear to mount the card in the first place.