Why my pc can npt connect 2 my book 2tb?

Hello, Sorry my Englisch is not as well but i have a problem,

i will connect another my book 2tb to my pc, but it doenst work, the pc everytime shows me only one of them but i will copy my files to the other my book 2tb.

can you help me?

If you are using 2 drives at the same time try looking in Disk Management. Make sure that both drives have different drive letters and that they are both online. If not assign or change the letter and put online if needed. That is the most common cause.