I know it's an old post, and the original poster has concluded it, by installing another opperating system, however; belloso2, The propper way would be to disable "KNOWN" items, one at a time. Testing each change~ (to ensure that you didn't cause any issues by disabling that startup item) ~by rebooting, doing normal stuff on your PC, then trying to shut down after testing. If it doesn't shut down, that startup item wasn't the cause, go back and re-enable it.. If you encountered an issue, that one thing you disabled can be quickly re-enabled etc.. Then move on to the next startup item rinse repete etc....

It's good that you were able to sort your shutdown issue down to ONE startup entry ~"WLAN"

Thanks for posting the culprit, you might try going a step further; maybe forward the information to microsoft to let them know what is going on, perhaps it's something they can fix and include in an update.