i create a programme that's used my hotmail account so i send e-mail to another account so it's worked but on another computers it's doesn't work and i don't know why in my laptop the programme work and in another laptops or desktops the programme don't do anything.
so i need your help!!!
thank you :)

What exactly does not work? its just the program wont start at all, or it crash at certain point?

no the program open normaly and in the send button nothing happened.

Can i see that piece of code? and what namespace are you using? System.Net.Mail?

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim SendMail As System.Net.Mail.MailMessage
Dim ServerSMTP As System.Net.Mail.SmtpClient = New System.Net.Mail.SmtpClient("smtp.live.com", 25)
ServerSMTP.UseDefaultCredentials = True
ServerSMTP.Credentials = New System.Net.NetworkCredential("from@hotmail.com", "password")
ServerSMTP.EnableSsl = True

SendMail = New System.Net.Mail.MailMessage("to@hotmail.com", "from@hotmail.com")
SendMail.Subject = "test"
SendMail.Body = TextBox1.Text

ServerSMTP.SendAsync(SendMail, Me)
Catch ex As Exception
Dim msg As String = ex.Message

If ex.InnerException IsNot Nothing Then
msg &= ". " & ex.InnerException.Message
End If

MessageBox.Show("An exception occurred with the message:" & Environment.NewLine & msg)
End Try
End Sub

Do the other machines have .net framework installed or updated?
Your developing machine is working fine because you have all the .net requisites.

Do you use a Reference in you program that is linked with a software that is installed in your machine i.e. "MSN messenger version XX"

no i don't use any reference just this code.
and i try it in pc that VS 2010 2008 and 2005 was installed (separately) i use VS 2005 but .net framework updated to 3.5 or i have 1.0 2.0 (VS 2005) and 3.0 3.5 (so here i have a question ,VS 2005 use .net framework 2.0 so if i have 3.5 it's automatically updated to 3.5 ? )and i try this in XP windows 7 and vista.
and i have asp.net send e-mail and it doesn't work either only in my laptop work.