Using string split with tab characters in PowerShell 1.0

(Get-Content -LiteralPath C:\temp\Users.txt) | ForEach-Object {$_.Split("`t")} | Set-Content -Path C:\temp\Results.txt

You're using the wrong escape character for the tab. Try this instead:

$f = Get-Content "Users.txt"

foreach ($line in $f) {
    $fields = $line.Split("`t")
    $fields.Count | Out-Host
}