Changed download URL's for manual download.

Added empty lines after PowerShell code.
And added a one-liner for the `RemoveZabbix.ps1` script.

Added some error handling in the one-liner script to install and configure a scheduled task fro `CheckAndStartZabbixAgent2.ps1`.

Added check to compare source and target files
Added code to handle if any source files is missing (for example if the network is down) to start service if not running.

Also remove Powershell check.

Fixed an issue where other logfiles got removed.
Added seconds to $currentDateTime.