We have received a couple of reports from Kaspersky Antivirus users of difficulty installing their Alfa product. We have confirmed with Alfa that in rare cases, having Kaspersky installed on your system may prevent a successful driver installation for your Alfa product. The solution is usually to just disable your antivirus software before doing the installation of the Alfa software, and then enable it again when installation is complete (a process very commonly recommended by various hardware and software providers to avoid conflicts).
In the case of Windows Vista, you may need to take some different steps:
1. Plug AWUS036NH and install IS_AP_STA_RT2870_D-126.96.36.199_VA-188.8.131.52_W7-184.108.40.206_RU-220.127.116.11_.exe
2. Open properties of the newly installed wireless connection
3. Disable (uncheck) the Kaspersky Anti-Virus NDIS 6 Filter (see image below)
4. Reboot PC with plugged AWUS036NH
5. Open properties of the wireless connection (go to Control Panel > Network Connections and locate the adapter, right-click and select Properties) and enable the Kaspersky Anti-Virus NDIS 6 Filter
6. Open Ralink Connection Utility, problem solved