Have you checked to make sure the computers are setup to retrieve IP and DNS information automatically? Also, are these computers connecting through the ASUS router, or connecting straight to the HT2000w?
How to set Network Adapter to Automatic
Oh, you are on an HT1100... sorry, thought you was on the HT2000w since there have been so many with that modem lately.
I suggest trying a third party DNS on your router or devices to see if that helps with the DNS errors, such as Google DNS, or Norton DNS. You may have to consult the manual for your exact model router to see how to change the DNS settings there.
How To Change DNS Settings to Google DNS
As for speedtests, the following should help, but we should aim to get the DNS issue resolved even if only temporary first:
Please keep in mind that Hughesnet will only accept testmy.net and the official Hughesnet speed test results. Tests from other sites like speedtest.net are not accepted due to the compression technologies and latency that satellite deploys.
Most important points to remember during this test:
-do the tests while directly connected to the HughesNet modem with a LAN cable (NO third party Router or Wireless devices can be used)
-use the 12MB size download test file ONLY if on Gen4 Service Plan
-use the 25MB size download test file ONLY if on Gen5 Service Plan
-If testing upload instead of download, you must use a 4MB size upload test file
-space each test at least 5 minutes apart
-post your results URL here, it may look something like http://testmy.net/quickstats/C0RR0SIVE
For a more in depth guide on running the tests, please visit: http://customer.kb.hughesnet.com/Pages/7001.aspx