Selecting Dynamic Folder When Searching For Files?

I have a file search that I want the user to select the folder they are searching the file in. At the moment I have
If Check.Text = "Correct" Then
If My.Computer.FileSystem.FileExists("C:Systemsfile.txt") Then
1CheckBox.Checked() = True
Else
1CheckBox.Checked = False
End If

However this check will be used for various files and its not usable if the FileExists directory stays the same ie searching the same folder and file for different records. I have a FolderBrowseDialog that I want the user to select the folder first in where to search and then within this chosen folder the static file will be checked. I have this as my folderbrowsedialog:

Dim Browser As New FolderBrowserDialog
Browser.Description = "Please select ."
Browser.ShowNewFolderButton = False
Browser.RootFolder = "c:"
Browser.SelectedPath = "c:windows"
If Browser.ShowDialog = Windows.Forms.DialogResult.OK Then
Me.text.Text = Browser.SelectedPath
End If

I tried adding in this code to the actual file check to encoporated the dynamic folder search but its bringing up errors and not working, I have this:
Dim path As String = "Browser"
Dim f As ReadOnlyCollection(Of String) = My.Computer.FileSystem.GetFiles("test.xlsx")
If My.Computer.FileSystem.FileExists("test.xlsx") Then
Box.Checked() = True