File Conversion problem in Microsoft Word!?!?

I saved a file about a week ago in Microsoft Word and when I try to open it a new option comes up asking me to "select the encoding that makes your doent readable." I check windows (default) and I get little boxes everywhere and none of the work I did. How do I fix this problem, I have a big paper due and that was it. Any help would be appreciated, detailed instructions, I'm not good with computers.