There is a sliding switch that locks down the cards. It is located on the left side of the phone as you have the back of the phone facing you with the back cover and battery removed.
Make sure you have the sliding lock switch slid in the up position(over the Simm card) and insert the memory card, then slide the lock switch down one click and this locks both simm card and the memory card in place. If you slide this switch down too far it will allow the simm card to be removed and only the memory card will be locked in place.
Hope this helps. Kindest Regards,
Hello. Just a quick follow-up to the problem with my co-worker's phone. I've read the section of the manual for my 6600 pertaining to memory card installation, and so far as I can tell, I'm attempting to install the card correctly, but it just won't fit. it's almost as if its too big or that there's something inside the phone preventing the card from falling into place properly. I don't remember having this trouble with my own phone, so once again, any help with this would be extremely appreciated. Missy