How do you do a file conversion?

How do you do a file conversion (encoding) on a Microsoft Office Word Doent? I want to open a file I originally had saved on my computer. Every time I try to open it up, however, it asks me what text encoding I would like to open it up in. I just want the default "Wester European (Windows) Encoding," which should be normal text, but when I open it up in this encoding, it gives me 10 lines of boxes and other weird symbols. HELP?!?!