I would look at it being something in Windows being corrupted.
IIRC, you can boot with "step by step confirmation". When it asks "run <whatever>" say yes and you'll see what is causing the lockup as that will be the last thing it runs before it fails. Then repeat the process, execpt this time tell that <whatever> NOT to run and repeat process as necessary until the beastie boots up. Then you'll know what you have to look for that needs repairing.
Might need Windows repaired/reinstalled, however.