Help - Lost Pictures

[Q-bert]

Needing help for a friend that took a series of head shots for a high school band. Everything went well until she try to upload her shots to her PC. She said she was able to view the pics on her Nikon (yeah I know :-?), but when she open up the SD card on her computer the pics where gone except the dozen or so shots that was there before today's shot. When she put the card back in her camera to see if she could view them there, they were gone.

Any ideas as to what might have happened or how to go about recovering the pictures if they are recoverable would be greatly appreciated.

BTW the computer was a HP laptop.

[joeseph]

you'll need a cardreader, but presume youl'll have one built into the laptop. Try running this freeware util: http://www.pcinspector.de/Sites/smart_recovery/info.htm?language=1
don't take any more pictures on that card until doing the file recovery - you will be overwriting potentially recoverable files.
What software did your friend use to open th files on the card? did it move the files to the laptop in the process?