How would I rename multiple computers in Active Directory using powershell referencing a CSV file?

Question

We are going to change the naming convention of our domain computers through AD and not making much progress. I export a csv file of computer names in a specific OU and then alter the CSV to have only 2 columns, old computer names and the new ones respectively. I want to change all computer names within the CSV file then restart the computer. I then tried getting the script to ask me for my domain admin credentials with no luck.

$oldname = "oldname"
$newname = "newname"
$computernameold = import-csv -Path "shareddrivepath" | select $oldname
$computernamenew = import-csv -Path "shareddrivepath" | select $newname

Foreach ($oldname in $computernameold) {
    Rename-Computer -ComputerName $computernameold -NewName $computernamenew Get-Credential
    Restart-Computer -Computername $computernamenew -force
}

pause