Your solution did not work for me. My 4GB Flash Drive did not become boot-able for me with the bootsectGui utility (even ran it as Administrator). Even though the bootsectGui utility stated all went well in its DOS Box window.
But I did find a very easy solution from Microsoft using a single executabe utility named "Windows 7 USB DVD Download Tool" which is documented step by step at http://arstechnica.com/business/news/2009/12/-the-usb-flash-drive.ars that worked like a charm for me. The Windows utility is downloadable from within the step by step article URL I give you here. My same 4GB Flash Drive above worked great with this utility.
I installed Windows 7 Ultimate 32-bit SP1 on my HP Mini 2140 netbook. It runs great.
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