VBA Exact Text Match - vba

Question

I am attempting to pull a column of letter codes using InStr from existing text files. I would like to allow this macro to be flexible enough to allow the option to manually input the letter code being searched.
Where I am running into an issue is when common numbers are in the letter code (i.e. C4 and C45). Originally the code was written to search for 2 specific letter codes, and I was hoping to be able to replace those 2 identifiers with a link to 2 cells.
No such luck, as I keep getting responses that are not exact. Please see the code below:
Private Sub CmdLettersGetfile_Click()
Dim objFSO As Object
Dim myDir As String, myList()
Dim objFolder As Object
Dim objFile As Object
Dim i As Integer
Dim sFolder As String
Dim fd As Office.FileDialog
Dim row As Long
Dim row1 As Long
Dim FCount As Integer
Dim FCount1 As Integer
Dim Val As String
Dim Pos As Integer
Dim Last1 As Long 'Mark the last row
Dim Start2 As Long
Dim Last2 As Long 'Mark the last row
Set fd = Application.FileDialog(msoFileDialogFilePicker)
For Each cn In ThisWorkbook.Connections
cn.Delete
Next cn
With ActiveSheet
Lastrow = Sheets("MAIN").Cells(.Rows.Count, "E").End(xlUp).row
End With
'
Worksheets("REPORT").Range("A6:AA1000000").ClearContents
Worksheets("REPORT").Range("A6:AA1000000").ClearFormats
row1 = 6 'Start of REPORT ROW
For row = 12 To Lastrow
sFile = Worksheets("MAIN").Cells(row, "E").Value
Pos = InStr(1, sFile, "org")
If Pos = 0 Then
Val = Worksheets("MAIN").Cells(9, "H")
Else
Val = Worksheets("MAIN").Cells(10, "H")
End If
Pos = 0
Dim strFilename As String
Dim strTextLine As String
Dim iFile As Integer
iFile = FreeFile
strFilename = folderName & "\" & sFile
Open strFilename For Input As #iFile
Last1 = 0
Last2 = 0
Do Until EOF(1)
Line Input #1, strTextLine
FCount = FCount
Pos = InStr(1, strTextLine, Val)
I cleaned up some of the irrelevant code in an attempt to save space and focus on the lines where I am having the issue.
********Update (26-Apr-2018 # 18:12 EST):
When I tried to format the Val to be one uppercase letter and 2 numbers
Dim Val As String: Val = "([A-Z]{1})([0-9]{1})([0-9]{1})"
I get the following:
Resulting data
Column I is the letter code that I need to get narrowed down.
*********Update 2 (27-Apr-2018 # 14:37 EST):
Expanded resulting data
I was able to mass redact what I needed to. I hope this offers more insight into what I'm looking to do.