..Row returns a Range object.
Try using set:
Use the .Row property of the range that is returned.
If you declare declare the variables then the VBE will give you
autocomplete options. It really helps in exploring the VBA.

Dim FoundInRow as Range
Set FoundInRow = Worksheets("Classes").Columns(*"C").Find(EnteredCR N,
_
LookIn:=xlValues, lookat:=xlWhole).Row
MsgBox ("FoundInRow = " & FoundInRow.Row)

Regards,
Jayant