SDHC slot doesn't work on macbook pro anymore... why?

Please,

The SDHC slot of my macbook pro doesn't work anymore. There are not dust and i've already tried other cards, but without success.

I've seen at various web foruns that it's a commum issue to other users of macbook pro.

I'll realy apreciate if you answer why it's happening AND what can I do to fix it.

Regards,

Heitor Gribl

Brazil