This is where document templates come in. When you open your new document, clicking File-New, you’ll have several templates to choose from. If you’re like me, you’ll usually just pick Blank Document. This is also the template that will be used if you click on the white sheet of paper button in the upper left of your screen (on the toolbar). With this in mind, open Blank Document, or whatever template you usually use.
Styles are the fonts and so forth that Word has picked out to match specific parts of your document - titles, endnotes, etc. Any changes you make are exceptions to the rules that Word uses. So next time around, it reverts to its rules and drives you crazy. You need to change the rules.
Go to Format-Style, click All Styles in the List menu. In the Styles menu, you now have all the styles Word will ever try to impose on your document. Select Endnote Text. Click Modify, click Format-Font. Make your changes, and click OK. Now you’re back in the Modify Style window; click “Add to template.” (I believe clicking “Automatically update” will allow you change all your previously typed endnotes, if you perform this procedure in your actual document, rather than in the template.) Click OK. Now back in the Style window, click Apply.
Go to File-Save As. Save as TheFifthYearsFavoriteEndnotesTemplate.dot. Next week, when you have to write another paper, just open this template, rather than Blank Document. Every time you open this template, you’ll have the styles you selected for it. Or, if you’re positive you’ll always prefer this, save it as Normal.dot, which is the file name for Blank Document.
Anyway, you can either paste your previous work onto your new template, or possibly do it on the fly, as I guessed at in the parentheses above.
Line spacing: Again, it’s just style. I’m not an expert on the difference between Normal, Body text, Body text2, etc. But in your current document when this annoys you, look at the toolbar at the top to see what style is governing your text. Then, go again to Format-Style, and select the appropriate name. This time, Modify-Format-Paragraph, instead of Modify-Format-Font.
I should point out that this is all true in Word 97 rather than 2000, but for the most part Word is Word.