Try this:

& "C:\Program Files (x86)\Microsoft Configuration Manager\AdminConsole\bin\i386\CmRcViewer.exe" PCNAME

To PowerShell a string "..." is just a string and PowerShell evaluates it by echoing it to the screen. To get PowerShell to execute the command whose name is in a string, you use the call operator &.

To run or convert batch files externally from PowerShell (particularly if you wish to sign all your scheduled task scripts with a certificate) I simply create a PowerShell script, e.g. deletefolders.ps1.

Input the following into the script:

cmd.exe /c "rd /s /q C:\#TEMP\test1"cmd.exe /c "rd /s /q C:\#TEMP\test2"cmd.exe /c "rd /s /q C:\#TEMP\test3"

*Each command needs to be put on a new line calling cmd.exe again.

This script can now be signed and run from PowerShell outputting the commands to command prompt / cmd directly.

It is a much safer way than running batch files!

One solution would be to pipe your command from PowerShell to CMD. Running the following command will pipe the notepad.exe command over to CMD, which will then open the Notepad application.

PS C:\> "notepad.exe" | cmd

Once the command has run in CMD, you will be returned to a PowerShell prompt, and can continue running your PowerShell script.

Edits

CMD's Startup Message is Shown

As mklement0 points out, this method shows CMD's startup message. If you were to copy the output using the method above into another terminal, the startup message will be copied along with it.