Aborted Download of App Update Messed up Play Store

[mizmercer]

Last week, I had to abort an app update mid-d/l. I couldn't get it to stop d/l, and in a rush, I stopped one of the process apps related to the Store app, now Play Store aborts and goes to home screen whenever I try to open it. I unfortunately need to add an app for a conference that starts in a couple days, available only through the Play Store. I've obviously bollixed things up rather badly, and short of a factory reset, I'm trying to figure out what to do. Suggestions appreciated.