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Microsoft has "Math Input Panel" built into Windows 7. It does not create LaTeX output and it is far from perfect, but it does allow you to write down an equation which is then typeset quite nicely.

http://windows.microsoft.com/en-us/windows7/use-math-input-p...

I relied on this a lot during my university days: http://detexify.kirelabs.org/

This is what you want:

http://webdemo.myscript.com/#/demo/equation