I have this program generating a firstname and lastname from a file. When I run this program I enter information in three textboxes. The first two are the salary low and h
You're using a new instance of System.Random every time. Random is seeded by the current time.
Initializes a new instance of the Random class, using a time-dependent default seed value
Reference
Since you are creating new instances in very quick succession, they get the same seed.
Instead, you should use the same instance of Random, possibly by making it a field and initializing as a field initializer or constructor. For example:
Public Class Form1
Private _random As New System.Random()
'Use _random in other methods.
End Class