They would be in the last folder that was used for saving files.
If you think you transferred them to the PC, they are definitely there. If you know any of the file names, run a search in Windows Explorer.
thank you- I found them on the computer, now can I put them back onto the sd card and how?
If you want it back on the SD card, just connect the SD card in a card reader and transfer (copy) the files over to the SD card. Please keep in mind that SD cards are not as reliable as hard drives. Therefore it is not a good idea to have data just on the SD card.
Personally, after I take pictures I transfer the pictures from the SD card (camera) to the hard disk on my PC. Then I make a backup of the PC. At this point, I delete the pics on the SD card, and re-use the SD card.