Memory card error

My little-used K100 D shows Memory Card Error in the screen every time I try to use it. There's nothing wrong with the card and I have tried several others just to be sure. Same result every time. I guess the camera is scrap?? Anybody had this problem and managed to fix it or find anybody else who can fix it? Batteries are fine. Everything else seems OK. I quite like this camera and am reluctant to scrap it. Any suggestion/help much appreciated. Peter H

The only thing I can suggest is to try cleaning the card slot. Start with an air blower and move on to inserting something if that doesn't work. As the camera is unusable as it is, you have nothing to lose.

Is this a card that you've used in the camera before or a new larger capacity one?
If it's a new high capacity card it won't be compatible so find an old low capacity card and try that (up to 2GB.) If you're on the original firmware the maximum capacity card it can use is 2GB. However if you can get a card recognised, update the camera firmware to version 1.02 which will then allow the use of SDHC cards which come in 4GB, 8GB and 16GB sizes.
Sometimes a default setting can help clear issues too.

Agree size of card in use is very important..