Windows - My Drive does not appear in Windows Explorer view

Method 2: Make sure that the drive has a drive letter assigned in Disk Management:

(This method applies to Disk Drives, USB flash drives or CD and DVD drives)

If your hard drive, thumbnail drive, memory stick, or flash memory is recognized in Disk Management but not displayed in Windows Explorer, the drive may not have been assigned a drive letter by Windows.

1. Open Computer Management by clicking the Start button, clicking Control Panel, and click System and Security viewed by Category View.
2. Click Administrative Tools, and then double-clicking Computer Management.
   If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
3. Look for a drive that does not have an assigned drive letter and is not labeled as System Reserved.
   
   Note: The System Reserved drive is reserved by Windows.
4. Right-click the unlabeled drive and click Change drive letter and paths…
5. Click Add and then click OK to select the first available drive letter.
6. If the Change drive letter and paths… option is not available, make sure that the drive is Online.
7. If the drive is Offline, right-click the disk number and click Online.

For more information on Adding, changing or removing drive letters for Windows 7, click the link below to see the article on the Microsoft website:

Change, add, or remove a drive letter

For more information on Adding, changing or removing drive letters for Windows Vista, click the link below to see the article on the Microsoft website:
Change, add, or remove a drive letter



Reference:
http://support.microsoft.com/kb/330140