Checking with an electronics store today, I was told it could be the SD card or the card reader in the computer. I purchased some SanDisk 4Gb #4 cards and they wouldn't do anything in the computer. Hooking my camera up to the computer by way of a USB cable everything worked. I could delete and reformat the SD card this way. Any card over 2GB puts it into SDHC. Checking the electronic store website, they list a 17 into 1 card reader which is good for 17 various cards etc. The price is $39.76 Canadian. This card reader connects to the computer with an enclosed USB cable.