Two things come to mind:
1 - Some windows files have gotten corrupted, causing the hang during boot. If this is the problem, a full reinstall of Windows will take care of the problem.
2 - Damaged HDD. If the damage is minimal, a full reinstall after a FULL format may resolve the problem. If the damage is deeper, then replacing the HDD is the only viable solution.
Realistically, if there is even minimal damage, you're probably better off replacing the HDD anyway, as those sorts of problems usually worsen over time.
I don't know that this is your issue. These are the first things that I would consider if I was facing your symptoms.