Powershell To Check Local Admin Credentials - powershell

Question

I'm trying to run a script that requires Administrator input in order to process certain things. Rather than have the script run unsuccessfully I'm trying to trap the error and throw it back into the Credentials, but I can't find a command I can pass Local Admin Credentials with to a Trap. Does anyone have anything that might work?
I've found MANY that will check domain credentials, but this is a LOCAL Admin account.
To clarify, I am using:
$Cred = Get-Credential
I need to verify the output from that is correct and has Admin access to run stuff further down in the script.
Working Solution (Thanks to User978511)
$Cred = Get-Credential
$Computer = (gwmi Win32_ComputerSystem).Name
$User = $Cred.Username
$Pass = $Cred.GetNetworkCredential().Password
$Users = ("$Computer"+"$User")
Add-Type -assemblyname System.DirectoryServices.AccountManagement
$DS = New-Object System.DirectoryServices.AccountManagement.PrincipalContext([System.DirectoryServices.AccountManagement.ContextType]::Machine)
$DS.ValidateCredentials($Users, $pass)
if ($Result -ne "True")
{
<Perform Tasks Here>
}

Answer 1

function Is-Current-User-Admin
{
return ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] "Administrator")
}

Answer 2

This will return you local admins (another answer is probably better fit here):
$group =[ADSI]"WinNT://./Administrators"
$members = #($group.psbase.Invoke("Members"))
$admins = $members | foreach {$_.GetType().InvokeMember("Name", 'GetProperty', $null, $_, $null)}
And this will check credentials:
Add-Type -assemblyname system.DirectoryServices.accountmanagement
$DS = New-Object System.DirectoryServices.AccountManagement.PrincipalContext([System.DirectoryServices.AccountManagement.ContextType]::Machine)
$DS.ValidateCredentials("test", "password")
All you have to do is to check that credentials are ok and that user is member of Admins group

Answer 3

# Test Local User Account Credentials
Write-Verbose "Prompting for password"
$pswd = Read-Host "Type password -- VERIFY BEFORE CLICKING RETURN!!!" -assecurestring
$decodedpswd = [System.Runtime.InteropServices.Marshal]::PtrToStringAuto([System.Runtime.InteropServices.Marshal]::SecureStringToBSTR($pswd))
Foreach ($computer in $computers) {
$temp = New-Object PSobject
$username = "variable with local admin user"
Add-Type -AssemblyName System.DirectoryServices.AccountManagement
$obj = New-Object System.DirectoryServices.AccountManagement.PrincipalContext('machine', $computer)
if ($obj.ValidateCredentials($username, $decodedpswd) -eq $True) {
Write-Host "The password of UserName $($username) in Computer $($computer) it is correct" -BackgroundColor Green}
else {
Write-Host "The password of UserName $($username) in Computer $($computer) does not is correct" -BackgroundColor Red}
}