From http://www.pp.co.nz newsletter
Show all of your Drives in Windows 7 Explorer
Depending on your system settings, when you go to computer in Windows Explorer, you might be in for a shock –> you may not see all your drives such as memory card readers if those drives are empty. If this disconcerts you, there’s a simple way for you to see them even if there’s nothing there:
1. Launch Windows Explorer and move below back-forward button and click on organize –> Folder and Search Options and move to View tab.
2. Under ‘Advanced settings’, uncheck box next to ‘Hide empty drives in Computer folder’. Click OK.
3. The empty drives would now be visible.