I'm running Windows XP in Virtual Box inside Windows 7. I selected a folder in Windows 7 for Virtual Box to share. However, when I'm in XP, I can't find the folder. Where is it?
dag729 asked if you've installed the Guest Additions, which is a good start. If you've gotten that far, check inside the Network Neighbourhood (or whatever it's called in XP) for a VBOX-type name (not sure of specifics) and it'll be there for you to map.