Nikon d3100 file names repeating?

I have the nikon d3100 and i don't know if it has to do with the camera or the memory stick… But when i insert the memory card into the computer to upload pics… There are 2 folders. I guess it fits a certain # per folder.anyway my question is that in like folder #2… The image name repeats… Like it'll start from 1 again… Like dsc… 001. But there's already a file with that name in folder #1.so it looks like its the same but its not. I know its confusing how i'm explaining but hopefully somoeone uderstands and can help. Like when i'm downloading to the computer the computer sees it as a repeat even though the pics are different! Get it? I don't accidenly want to over-write the image. But how do i get it to not use the same file name?

The default setting is to have the image files sequentially accumulate until you have shot 9999 images, then it starts over at 0001.

Make sure you have that set up in your cameras menu and then all those problems will disappear.

NOTE: The Nikon D3100 does NOT use Memory Sticks, those are a proprietary memory card made for certain Sony cameras Your camera uses SD and SDHC memory cards, just to be clear

Set the "File Number Sequence" to "ON" in the Setup Menu.

This tells the camera to start counting up from the last file number used. You probably have this feature set to "OFF" which tells the camera to start it's file numbering at 0001 each time you turn on the camera and start taking pictures.

Hope the info helps and happy shooting:-)