function sendMail($srv, $DriveName, $free) {
	$subject = "Low Drive Space on $srv"
	$body = "<p style='font-family: calibri;'>The <B>$DriveName</B> on server <B>$srv</B> has only <B>$free % </B> free.<BR/>
	Please try to free up some space so it is above $percentThreshold% free space.
	</p>"
	
	# Init Mail address objects
	$emailFrom = New-Object system.net.Mail.MailAddress "donotreply@yourcomany.com" , "Low Drive Space on $srv"
	$emailTo = New-Object system.net.Mail.MailAddress $alertEmail , "Low Drive Space"
	$smtp = new-object Net.Mail.SmtpClient($mailServer)
	$MailMessage = new-object Net.Mail.MailMessage($emailFrom, $emailTo, $subject, $body)
	$MailMessage.IsBodyHtml = $true
	
	$smtp.Send($MailMessage)
}

function CheckDriveSpace($servername)
{
	$drives = gwmi win32_logicaldisk -filter "drivetype=3" -ComputerName ($servername) -ErrorAction SilentlyContinue
	foreach($drive in $drives)
	{
		$PercentFree = [int]([Int64]$drive.FreeSpace / [Int64]($drive.Size) * 100) 
		
		#SaveDriveinfo $ServerName $Drive.DeviceID $Drive.FreeSpace $drive.Size $PercentFree
		
		if($PercentFree -lt $percentThreshold)
		{	
			sendMail $servername $drive.DeviceID $PercentFree
		}
	}
}

function Main()
{
	try
	{
		$servers = Get-Content("C:\Servers.txt")
		foreach($server in $servers)
		{
			CheckDriveSpace $server
		}
		return 0;
	}
	catch
	{
		# Handle the error
		$err = $_.Exception
		write-host $err.Message
		while( $err.InnerException ) 
		{
			$err = $err.InnerException
			write-output $err.Message
		}
		return 1;
	}
}


Clear-Host
$percentThreshold = 15
$alertEmail = "dba@yourcompany.com"
$mailServer = "mail.yourcompany.com"
Main