If I'm working in Microsoft Word in Windows XP and I save my work on a flash
drive and open on my computer at home which has Vista installed on it, will
my document open?
This has nothing to do with Windows XP vs. Windows Vista. It's only a
matter of the Word application.
First you have to have Microsoft Word on both machines.
Second, you have to have a compatible version of Microsoft Word
installed on both machines, but that's highly unlikely to be an issue
going from an XP machine to a Vista one.
And third (also highly unlikely) there is one other potential
incomparability to be aware of. If your XP machine has Word 2007 and
you save the file in the new default docx format, and your Vista
version is an older one, it won't open the docx file unless you're
installed the additional code to let older versions read docx files.
I mention points 2 and 3 just to be complete. In all probability, as
long as you have Word on your Vista machine, you should be all right.