You have to use the HT2000W modem for HughesNet's service. There's no way around that. You can, however, use a 3rd party router with HughesNet if you'd rather not use the HT2000W's built in WiFi.
Is your service currently down? If so, try going to http://192.168.0.1/#!/home/status, preferably with a LAN cable connected device, and let us know what the State Code is near the top of the page. Both the number and description.
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