Thanks, ashleyg. The link you sent didn't work for me. When I reached step 7, "Click the OK button," there was no OK button to click on. Instead, there was an Open button. Clicking it didn't get me to where I was supposed to be. (I went through this process twice, with the same result.)
So I put my old outlook.pst file in the Documents>Outlook Files folder, where it showed up as Archive Folders along with an Outlook Data Folder that must have gotten created automatically somewhere along the way. Then I went into Account Settings, where both folders were listed on the Data tab, and selected Archive Folders as the default. I also changed the name to Active Folders. When I manually configured my e-mail protocols, I chose that location for my PST file, and things are now working properly. Should I mark this question as solved, even though I didn't solve it the way I was supposed to?