Depends on the site, some might use you hostname to detect language, but most sites (including msgpluslive.net) just use your browser's preferences...
Clear your cookies first.
IE: Tools > Internet Options > General > Languages > Add the language you want and put it on top
FF: Tools > Options > Content > Languages > Add the language you want and put it on top (or use the
Quick Locale Switcher add-on)
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