Phoenixedia_127

I downloaded a mod pack called arnarchyearth, and when I opened it for a few minutes it closed. It did this twice, so I just left it alone, and opened up another mod pack. Today, I discovered the the previous mudpack (arnarchyearth) was still running. I right clicked it, and then clicked quit; it didn't quit. I tried doing that a few more times over the course of an hour, and nothing happened. So I deleted it. After that, when I went to shut my computer off, it wouldn't shut off because the modpack arnarchyearth wouldn't close. So basically, I downloaded this texture pack called arnarchyearth, and then I deleted it contents, but it is still running, and won't close. What do I do?