How do I get to my pictures off my SD card onto the computer when the computer won't recognize it?

I put the memory card from my camera into it's slot on my tower. Normally when the card ges in a screen will pop up asking me what to do with the pictures. When the screen didn't pop up I went in through 'My Computer' and clicked on all the 'Removable Disk' drives and all of them said they were empty.. All I want to do is transfer pictures from my memory card onto my computer..help please.