Press Windows key + X. Click Disk Management. If you see your drive listed there, but no drive letter, right click it. Click Change Drive Letter and Paths. Click Add. Click Assign the following drive letter. Click in the Drive letter list box. Choose a drive letter - try choosing letters near the end of the alphabet. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.