I agree with Mark. I also am a EE and the memory cards should not be able to harm your computer or your camera, even if you have a bad one. Even thought the cards pass electricity through them, the origional signal is coming from the card reader and it is either a 1 or a 0...on or off. The card does not generate any electrical signal of its own, it simply manipulates the signal coming from the reader to indicate on or off. That said, the only way the card could generate an electrical charge is if static electricity was built up in the card from some external source. The static electricity would have discharged when you inserted it into the first card reader (camera or computer), so if the card is still working, it should be fine now. I highly doubt that static electricity was your problem...just trying to cover all bases. Bottem line, it was probably the reader in the camera and should be fine now. (I also have a coolpix 5700 which has occasionally suffered the same lockup, but the same cards have never caused a problem in my D70). Hope this helps.