Since the OP said he only wanted to search a single sheet, an alternate to the red highlighted line of code is this one...
Code:
Application.Dialogs(xlDialogFormulaFind).Show
which has the small advantage that the user does not have to click the "Options>>" button in order to be able to specify that the search should be case sensitive or that the text being searched for is the only text in the cell. Another advantage is that you can specify the default options directly. For example, if you wanted to specify the text "Peter" as the preloaded default, you would just add it as the first optional argument like this...
Code:
Application.Dialogs(xlDialogFormulaFind).Show "Peter"
In addition, if you wanted the "Find what" field to always default to an empty field (the default is for the field to use the last text that was searched for), just specify the empty text string ("") like this...
Code:
Application.Dialogs(xlDialogFormulaFind).Show ""
The second optional argument controls the "Look in" search argument... 1 for Formulas, 2 for Values, 3 for Comments. So, if you wanted to search for the text "Peter" in the cell values, you could force those options this way...
Code:
Application.Dialogs(xlDialogFormulaFind).Show "Peter", 2
I'll omit the example code for the remaining options as I think they are fully straightforward. The third optional argument controls whether the text being searched for must fill the entire cell or not... 1 puts a check mark in that option's checkbox and 2 omits the check mark. The fourth optional argument controls whether the search order will be "By Rows" or "By Columns"... 1 for "By Rows" and 2 for "By Columns".
I could not determine what the fifth argument controlled... it will allow you to specify any number (positive or negative), and only a number, but nothing seems to change when you specify it. The sixth optional argument controls whether the search will be case sensitive or not... 1 puts a check mark in that option's checkbox and 0 omits the check mark (note that the number scheme for this checkbox is... strangely... different than for the "Find entire cells only" checkbox).