You need to assign drive letter to it.
After that you'll need to format it, if you did not already.

Quote:1. Log on as Administrator or as a member of the Administrators group.
2. Click Start, click Control Panel, and then click Performance and Maintenance.
 
Note If you do not see Performance and Maintenance, go to step 3. Performance and Maintenance appears in Control Panel only if you use Category view. If you use Classic view, Performance and Maintenance does not appear.
 
3. Click Administrative Tools, double-click Computer Management, and then click Disk Management in the left pane.
4. Right-click the drive, the partition, the logical drive, or the volume that you want to assign a drive letter to, and then click Change Drive Letter and Paths.
5. Click Add.
6. Click Assign the following drive letter if it is not already selected, and then either accept the default drive letter or click the drive letter that you want to use.
7. Click OK.

Dear Wilhemus,
 
Thanks so much for the reply. I went to the folders as you asked, and I see my "missing" partition. It says
 
Disk 0
Basic
55.88mb
Online
 
and then to the side is says C: 27.95GB (Healthy) and 27.94GB (unallocated).
 
When I right click the unallocated (which is the one I cannot view in Windows), I don't get the options that you state. I only get "new parition..." "properties" and "help". Does this mean my option is to choose the new partition?
 
When I right click my C: I do see the options you talked about.
 
 

Yes, in Disk Management, you'll need create a new partition from the unallocated space, then format the new partition and assign drive letter to it.