If your Windows 7 or Windows Server stops responding at the “Please wait” screen before you are requested to press Ctrl+ALT+DEL, this hotfix may be able to help you!
Windows 7 freezes at the Please Wait screen
Let’s say you try to start a computer that is running Windows 7 or Windows Server 2008 R2.
However, the operating system stops responding at the “Please wait” screen that appears before you are requested to press Ctrl+ALT+DEL.
Therefore, you cannot log on to your Windows computer.
In such a case download and apply Fix314380 from KB983551. [UPDATE: It appears that this hotfix is no longer available]
This issue occurs because an auto-start service remains in the pending mode for too long and cannot start during the Windows startup process. This is caused by a deadlock that occurs because of an interaction between Windows Error Reporting (WER) and AppLocker.
Read: Windows is stuck on loading some screen.