txt file size?

[alexta]

Option Explicit
 
Private Sub Form_Load()
  Dim ff As Integer
  Dim strBuff As String
  Dim str() as string
  ff = FreeFile
  Open "c:\text.txt" For Input As #ff
    strBuff = Input(LOF(ff), ff)
  Close #ff
  str() = split(strbuff, vbcrlf)
  msgbox "There are " & ubound(str) -1 & " sentences in the file"
End Sub

Hello! Can this code be used to search a text file for a string? When I tried it it worked but not on the whole file. I suppose the file is too big to load in a string. Is there a way around this without going into complex hardcore coding? Sorry but quite limited VB skills