Scripting

This script will add a machine name to a collection (once you configure the constants at the top).  It isn't my script (I won't take the credit...) but it works well from memory:

 '########## PARAMETERS ###############
 
'Define the target collection using the CollectionID value
Const CollectionId = "CEN003A5"
 
'Define the SCCM Site Server
Const SiteServer = "TAL001"
Const SiteCode = "TAL"
 
'########## PROGRAM ###############
 
Dim sResourceID, oSMS
Dim wShell : Set wShell = WScript.CreateObject( "WScript.Shell" )
 
'Use the local computer value as the target machine
Dim sComputer : sComputer = wShell.ExpandEnvironmentStrings("%COMPUTERNAME%")
 
'Main Program Runs Here…
wScript.echo sComputer
Call ConnectToSite() : 'Connect to Primary Site Server
Call AddMachineToCollection() 'Add machine to specified collection
 
'########## FUNCTIONS ###############
 
'Query site for machine and return resource ID
Function FindMachine
 
    'Query WMI for the machine
    Set oResults = oSMS.ExecQuery("SELECT * FROM SMS_R_System WHERE Name = '" & sComputer & "'")
 
    For Each oResourceID In oResults
        FindMachine = oResourceID.ResourceID 'Return the result of the query
    Next
End Function
 
'Connect to the SCCM server
Sub ConnectToSite()
 
    On Error Resume Next
    Set oLocator = CreateObject("WbemScripting.SWbemLocator")
 
    'Connect to the SCCM Site Server
    Set oSMS = oLocator.ConnectServer(SiteServer, "root\sms\site_" & SiteCode)
 
    'Quit the script with an error message if unable to connect
    If Err Then
        Err.Clear
        wScript.echo "Cannot connect to SCCM."
        wScript.Quit
    End If
 
    wScript.echo "Connected to " & SiteCode
    oSMS.Security_.ImpersonationLevel = 3
    oSMS.Security_.AuthenticationLevel = 6
End Sub
 
'Create a membership rule to add the machine to the collection
Sub AddMachineToCollection()
 
    'Return the resourceID of the machine
    sResourceID = FindMachine
 
    'Set the machine collection
    Dim oCollection : Set oCollection = oSMS.Get("SMS_Collection.CollectionID=" & """" & CollectionId & """")
    'Create a membership rule
    Dim oCollectionRule : Set oCollectionRule = oSMS.Get("SMS_CollectionRuleDirect").SpawnInstance_() 
 
    'Define the membership rules properties
    oCollectionRule.ResourceClassName = "SMS_R_System"
    oCollectionRule.ResourceID = sResourceID
    oCollection.AddMembershipRule oCollectionRule : 'Create membership rule
 
    wScript.echo "Added to collection."
End Sub

although based on your question, you'll probably want to replace this line:

 Dim sComputer : sComputer = wShell.ExpandEnvironmentStrings("%COMPUTERNAME%")

with this:

 Dim sComputer : sComputer = InputBox("Please Enter your Machine Name:","Please Enter your Machine Name")

you can just run a query to find out the collection id and you can add or delete .. i could not find my complete script... but remeber below object... will try to get it posted soon.

    Set col = objSMS.Get _

    ("SMS_Collection.CollectionID='" & strCollID & "'")

Col.Delete_