One of my friends just recently got MineCraft, but is having major issues with it. He's downloaded the launcher, but whenever he tries to run it, the launcher doesn't start, at all. No messages or whatnot, it just doesn't appear.
He has the latest java, and he was able to run it on the browser. It's not an administrator problem either, since he has administrator privileges and has tried running it with them (with the same result). So what is the problem, and how can it be fixed?