Chocolatey doesn't install - powershell

Question

Following the steps to install Chocolatey via Powershell doesn't work on my Windows 7 64bit PC. I'm following https://chocolatey.org/install#install-from-powershell-v3
I have confirmed the ExecutionPolicy and that system path has
Powershell;
PS C:\Users\a> Get-ExecutionPolicy
AllSigned
PS C:\Users\a> ($env:Path).split(';')
%SystemRoot%\system32\WindowsPowerShell\v1.0\
C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common
C:\Program Files (x86)\Intel\iCLS Client\
C:\Program Files\Intel\iCLS Client\
C:\ProgramData\Oracle\Java\javapath
C:\Windows\system32
C:\Windows
C:\Windows\System32\Wbem
C:\Windows\System32\WindowsPowerShell\v1.0\
C:\Program Files\Java\jre1.8.0_40\bin
C:\Program Files\Java\jdk1.8.0_40\bin
C:\Program Files (x86)\AMD\ATI.ACE\Core-Static
C:\Windows\System32\WindowsPowerShell\v1.0\
C:\Program Files\Intel\Intel(R) Management Engine Components\DAL
C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL
C:\Program Files\Intel\Intel(R) Management Engine Components\IPT
C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\IPT
C:\HashiCorp\Vagrant\bin
C:\Program Files (x86)\Git\bin
C:\Program Files (x86)\Skype\Phone\
C:\Program Files (x86)\Git\bin
C:\Program Files (x86)\Git\libexec\git-core
C:\Program Files (x86)\Nmap
C:\Program Files\smartmontools\bin
Here are my error messages;
PS C:\Users\a> iwr https://chocolatey.org/install.ps1 -UseBasicParsing | iex
???# : The term '???#' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ ???# =====================================================================
+ ~~~~
+ CategoryInfo : ObjectNotFound: (???#:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException
Getting latest version of the Chocolatey package for download.
Getting Chocolatey from https://chocolatey.org/api/v2/package/chocolatey/0.10.5.
!Test-Path : The term '!Test-Path' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
At line:188 char:11
+ } elseif (!Test-Path $7zaExe) {
+ ~~~~~~~~~~
+ CategoryInfo : ObjectNotFound: (!Test-Path:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException
Extracting C:\Users\a\AppData\Local\Temp\chocolatey\chocInstall\chocolatey.zip to C:\Users\a\AppData\Local\Temp\chocolatey\chocInstall...
Exception calling "Start" with "0" argument(s): "The system cannot find the file specified"
At line:211 char:3
+ $process.Start() | Out-Null
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : Win32Exception
Exception calling "BeginOutputReadLine" with "0" argument(s): "StandardOut has not been redirected or the process hasn't started yet."
At line:212 char:3
+ $process.BeginOutputReadLine()
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : InvalidOperationException
Exception calling "WaitForExit" with "0" argument(s): "No process is associated with this object."
At line:213 char:3
+ $process.WaitForExit()
+ ~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : InvalidOperationException
Unable to unzip package using 7zip. Perhaps try setting $env:chocolateyUseWindowsCompression = 'true' and call install again. Error: 7-Zip signalled an unknown error (code )
At line:225 char:15
+ default { throw "$errorMessage 7-Zip signalled an unknown error (code $exitC ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : OperationStopped: (Unable to unzip...n error (code ):String) [], RuntimeException
+ FullyQualifiedErrorId : Unable to unzip package using 7zip. Perhaps try setting $env:chocolateyUseWindowsCompression = 'true' and call install again. Error: 7-Zip signalled an unknown error (code )
I have tried the error messages suggestion on the last line
Perhaps try setting $env:chocolateyUseWindowsCompression = 'true'
But that only results in a whole series of other errors

Answer 1

PS C:\admin\scripts> iwr https://chocolatey.org/install.ps1 -UseBasicParsing
StatusCode : 200
StatusDescription : OK
Content : # =====================================================================
...
You're downloading a UTF-8-encoded file (the content begins with the characteristic UTF-8 byte order mark ), but it's being treated as ASCII text.
Besides:
I'm following https://chocolatey.org/install#install-from-powershell-v3.
No, you're not. The website you referenced tells you to use
iex ((New-Object System.Net.WebClient).DownloadString('https://chocolatey.org/install.ps1'))
which works as advertised, whereas you're trying to use
iwr https://chocolatey.org/install.ps1 -UseBasicParsing | iex
If you want to use that approach you need to remove the BOM from the content before piping it into Invoke-Expression:
(iwr https://chocolatey.org/install.ps1 -UseBasicParsing).Content -replace '^' | iex