killall didn't work, unfortunately . . . but by trying at random intervals, I've found that my computer will sometimes shut down or restart normally; sometimes it'll require me to choose it twice (as in, go back into the start menu and pick "shut down" a second time before it'll shut down); and sometimes it'll do nothing, as I previously described. But if I have to pick it more than twice, it won't work no matter how many times I try. I'm not at home right now, but when i do get home I'll download HijackThis and post the results.