Why won't my camera read my sd card?

I was browsing through my pictures on my nikon d3100 and deleted some photos. I took the sd card out and uploaded the remaining photos to my laptop. After I uploaded them, I put my sd card back in the camera and it says "no sd card inserted" when it's clearly in.

You are lucky that the images did not become corrupt.

Number one rule: Forget there's a delete button on your camera

Follow this workflow and you will probably never have a card become corrupt.

* Start your shooting day with a freshly formatted memory card, formatted in your camera
* At the end of the shooting day, copy all the images to a new file folder on your computer using a card reader and named for the subject/location and date so you can find them years later
* Once the images are safely on the computer, format the card.

Do this routinely and you will rarely have an issue with corrupt files or cards.

Remember to copy all the image files, do NOT move them. Moving them takes them off your memory card and if in the process, one or more of the images has become corrupt during the transfer, you have NO second change to recover the file.

This will probably fix your problem:

It works most of the time, but nothing may work 100% of the time. Still, it is worth trying.