USB cord for Nikon D3100?

I left my cd software at home,
is there any way my nikon will connect to my computer just with the USB?
i can't seem to get it to read it!
i have a card reader, but it will not read the memory card for some reason?

Go on the Nikon Website and put your Camera model in there might be the software you can download on the site. I tend to do this with a lot of electronics