An error message is displayed during windows startup about a service that has failed to start, and then the system locks up. you try to boot into safe mode, but get the same error message. what do you try next?

Try the System Recovery Options

Explanation: The reasons that a system locks up on startup can be operating system failure, corrupt system file, missing file, virus attack, hardware problems like damaged hard drive, motherboard failure, corrupted RAM etc. One of the subtle ways is to use system recovery tools if a system fails to boot up into Safe Mode.

System Recovery Options: It is a collection of diagnostic tools that help to recover, repair and restore Windows system. The two important options that can be used to fix the given problem are: Startup Repair and System Restore. You can choose these options from Advanced Boot Options or from the Windows installation disk.

Startup Repair: It can fix certain issues that are preventing the system to start by scanning the computer and trying to repair issues such as damaged or missing system files.

System Restore: It is a tool that reverts a computer back to a previous restore point, if that point was created. Restore point is a snapshot of registry or system files. So this tool returns the system to its previous working state, returning it to settings stored in the restore point.