Program freezes with specific numbers - vb.net

Question

This code is supposed to take a number and find it's prime factors.
Why does this code work with numbers like 2345 (which returns 5, 7, 67 like its supposed to) but it doesn't work with numbers like 500 and 800?
EDIT: when I say it doesn't work, the program simply does nothing and/or freezes on button click. I then have to stop the program in vb.
Dim number As Double = txtNum.Text
Dim var As Double = 2
Dim result As Double
If number > 1 Then
lst1.Items.Clear()
lst1.Items.Add("The prime factors of " & number & ":")
Do While number > 1
result = number / var
If result = Int(result) Then
lst1.Items.Add(var)
number = result
End If
var = var + 1
Loop
Else
lst1.Items.Clear()
lst1.Items.Add("Let try that again...")
End If

Answer 1

The problem was caused because 500 divided by 2 is 250, divided by 5 is 50 ... and then the program continued on by dividing by 6 instead of attempting to divide by 5 again. Once var reached 10, number became 5 and no further divisions ever allowed it to reach 1 - thus an infinite loop was created.
By changing
If result = Int(result) Then
lst1.Items.Add(var)
number = result
End If
var = var + 1
to
If result = Int(result) Then
lst1.Items.Add(var)
number = result
Else
var = var + 1
End If
it correctly made multiple divisions by the same prime factor when necessary.