image cannot be displayed

can anybody help, im using a 4gb sandisk and a 4gb sandisk extreme in my pentax kx which i bought brand new in august 2010,all was ok now im getting a message on the camera saying image cannot be displayed?,
when the sd card is in the card reader then put through my laptop the images that couldn't be displayed are there. has anybody had this problem or know what it could be

Probably the Sandisk cards. Try a different make such as
Lexar.

Thanks Algi...yeh thats what i was thinking of doing...but i always thought sandisk were the best???

Have you formatted the card in your camera?

When I put my card through the pc card reader then place back in my K20 it shows "Card full!"....even though it's not,I re formatt the card in camera and everything is fine!....be worth a go!

They are certainly one of the best assuming you got genuine ones. I have had 4 for about two years and no problems at all.

You didn't get them cheap off Ebay did you? There are some forgeries about.

Before reformatting them - have you tried a recovery program to get any images off them?
Have a Google and you will find some programs. It may be worth a try.

The program that Sandisk provide free with their cards (Rescue pro?) works well.

I've never had a free program from them .

My images aren't worth rescuing

But on the topic of duff cards, they do seem to throw a tantrum occasionally, I have one that occasionally the reader will tell me I cant read an image, when you click "try again" it works OK, been doing it for months. I cant remember which card it was, I might even have left it in the K20D when I posted it to CardifGareth

I started buying Transcend after getting a class 6 at a knockdown price a few years ago, just bought a 16gig class 10 for the K5, mainly for video.

I thought most of them had it. It comes in the form of a leaflet with a number on. You go to a website and download the program and enter the number and they give you a serial number which unlocks the program.