Aztech WL552USB is cheap now, I believe many people have got it, some Windows 7 users may facing same problem as me,

Problems
-Detects the radio type of the wireless n network incorrectly
-Couldn't connect to / failed to connect a wireless network that detected in range.
-Frequently disconnection even after successful connected
-Sometimes connected, but no internet access
-Couldn't assign an ip address or using manual configured ip address

Driver from Aztech website v1.0 or from Driver Disc which is only compatible for Windows XP, Windows Vista, does not support Windows 7,
- Detected correct wireless n network, but still unable to connect same as problems above
Here's the WL552USB Ralink drivers for Windows 7:

Ralink - Network - 802.11n USB Wireless LAN Card

http://catalog.update.microsoft.com/v7/sit...link%20wireless
Drivers download for Windows 7 32bit and 64bit (Ralink Wireless N USB Adapter Driver v3.1.0.0)

Windows 7 32bit
http://www.megaupload.com/?d=IJOWJNDF

Windows 7 64bit
http://www.megaupload.com/?d=N8FS6RNN

Ralink chipset driver for Windows can be downloaded at http://www.ralinktech.com/support.php?s=1
Thanks cshong for the link

Installation:

Extract files from the *.cab file you have downloaded to a new folder, I use WinRAR,

Plug in your Aztech WL552USB, go Device Manager (Right click "Computer" -> "Manager" -> "Device Manager")

under "Network Adapters" tree, choose "802.11n USB Wireless LAN Card"

right click it, select "Update driver software", then select "Browse my computer for driver software"

then browse the folder where you extract the driver files to, click "Next",

now it should be updated, you Aztech WL552USB is now working like it should be.
You can also obtain this driver by plug in your WL552USB, and go check for windows update, under Optional Updates section, current version is v3.0.7.0
I recommend you to get it from the megaupload links above or from catalog.update.microsoft.com for latest v3.1.0.0

did anyone have difficulty to connect the usb adaptor to unifi router?

Thanks to you I finally found the driver to make this stick works in OSX Lion!! Ralink actually provides the driver for OSX, but Aztech is just so freaking lazy to update the drivers on their website! They don't even update the Windows driver, let alone includes the OSX driver. Thank you again!

did anyone have difficulty to connect the usb adaptor to unifi router?