Couple of things to try, some may be redundant with previous posts, and I apologize if they are:
1) Try going to
http://www.foamsupplies.com/ and see if you can access the page
2) If you can't access the website, go to a command prompt and ping foamsupplies.com
(start>Run>>type "cmd" a command prompt will open, then type ping foamsupplies.com) It should return an IP Address of 209.200.116.64 then post the results.
3) If both trying to access the website does not work, and an IP Address is not returned when you try to ping foamsupplies.com, then try the ipconfig /registerdns command, then try both again.
4) While you are in the command prompt, also type "ipconfig /all" and post the full results of that as well please.
Note: I know that you've tried this before, with suggestions from this thread, but I wanted to have you try it again with a web-site that you very likely have not tried going to to elimate the cache from interfering.
And a couple questions as well:
1) What kind of internet connection are you using (dsl, cable, dialup, etc..)
2) Are your computers networked together with a hub/switch/router?