gistfile1.txt

foreach ($comp in $computers) {
    New-PSSession -ComputerName $comp -Credential $Credential
    $TargetSess = (Get-PSSession -ComputerName $comp -Credential $Credential | where {$_.State -eq 'opened'})
    $destination = "c:\scripts\R"
    Copy-Item \\source\R\* -Destination $destination -ToSession $TargetSess -Force
    $ScriptBlock = {
        cd "C:\scripts\R";
        . .\Remove-PreviousOfficeInstalls.ps1
        Remove-PreviousOfficeInstalls
    }
    Invoke-Command -SessionName $TargetSess -ScriptBlock $ScriptBlock -AsJob -JobName $comp -Verbose  
}