If I remember correctly then Windows can limit the amount of ram available depending on the operating system. So just a few questions, some might seem stupid but just to make sure. Are you 100% that you're using 7 Ultimate? I think the Starter edition limits it to 2gb which is the issue you're having. Have you tried having just the new 4gb ram stick in the pc? I know that some can get funny if you have different RAM sizes.
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