Vista can be a pain in the butt sometimes >:o
You can try checking to see if your antivirus/firewall is messing with it, otherwise try running the client as an admin (you can right click it, go to properties and there should be an option to have it always run as an admin). Speaking of programs, do you have others running when you try to load up hero? for some reason my hero client freezes up when i "allow" something to go (for example if I were to update java and the little allow window shows up).
Another thing you could try is running task manager and seeing how long the process runs until it crashes and dies :o vista has a knack for doing that with alot of programs (My version of vista likes to destroy skype <
that way you can try and see what's interfering with the client x3 If all else fails, you'll have to do as the previous persons have said and re-install hero :c Best of luck to you, fellow vista user ;w;