New HDD not seen in windows explorer

After fighting my way through getting W7 installed successfully, I find that I can see the SSD (drive C), the optical drive (Drive D), but the 1TB HDD I installed for data is not there.

It is listed in the hardware manager, but not in windows explorer. I am sure there is a way to assign a letter so that it is visible, but I do not know how.....<sigh>

Thanks in advance...  : )