I'm still confused as to why psexec is the remote shell of choice when WinRM offers all of the same benefits but with a single port opening in the firewall.
It does need configuring but probably less than PSExec. No problems if you've settled on psexec already, I'm just offering additional options. :)
Really quickly you need to execute winrm quickconfig
on the machine that you wish to control. This quickstart command alters a number of settings throughout the system so it's worth investigating if your security policies allow this before you run it.
Once run, you can use WinRS like this:
WinRS -r:Computername ipconfig
You can, if you don't already have permissions on the target system, run the command with other credentials.
WinRS -r:Computername -u:Username -p:Password ipconfig
You can also use PowerShell commands on remote machines configured for remote management. From within Powershell management
Invoke-Command hostname {powershell-command}
or icm hostname {powershell-command}
If you have the right infrastructure, WinRM and WinRS can replace the need for psexec and the quickconfig command makes setup simple enough.
Cheers
Lewis