I had this problem also. I am running a desktop running Win7 Professional 64 bit. Symptoms were that during installation of the device, i received a "network adapter not found" error message. Then after completing the installation, Device manager saw this adapter "working correctly" but the adapter could not automatically detect any wireless networks. After some research, I found a solution.
1. Insert Dlink CD into CD Drive
2. Do NOT install the Wireless Configuration software from CD
3. Insert device into USB port
4. Do NOT let windows install software drivers for it automatically
5. Go to Control Panel, then device manager
6. Go to top of window and select "Action" --> Scan for hardware changes
7. Find the adapter device, ie. 11n adapter (or something like that)
8. Select Device, then right click, "Update Driver Software"
9. Load the XP 64-bit driver from the CD
10. Let Microsoft Windows manage your Wireless Networks (not the Dlink Wireless Config sfw).
This worked for me.