Won't open at all

[rileysami]

When I click Amnesia to launch it, it doesn't open at all. The loading sign appear for a second, but will dissapear and it will stay at my home screen. It worked for the past week, and we have made no updates to our laptop whatsoever. Our version of Windows is Windows XP series 2. It says it is not compatible, when like i said before, we have been using it for the past week. HELP!

---

How can I reinstall the game without having to pay for it again??