Be sure to review this post:
Once you have followed the steps in that post, you go to the official download page using either IE or Firefox. Your operating system should be automatically detected. You can also choose Locales and Languages to select the appropriate version - XP 32 bit only, or the 32 bit or 64 bit version for Vista/Windows 7. MSE will not install on XP64. If your hardware is 64 bit, but your OS is 32 bit (x86) XP, Vista, or Windows 7, you need to use the 32 bit version of MSE.
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