Sorry for the slow reply. You're question is still pretty vague, but if I understood you correctly, then here is an idea. Put this code in the Sheet1 object or whatever sheet(s) you want to modify. It will slow down your performance significantly because the macro runs every time you select a new cell. It adds some highlights to a cell when it is selected, and only when it is selected.
The downside is that all formats are cleared when you select a different cell. So any formatting you have anywhere on the sheet will be cleared every time you click the mouse in a cell or hit an arrow key. You could maybe modify this to only clear the formatting in the target cell, but I don't know how to do that off the top of my head. If you want the bold/outline to stay when you select a different cell, then simply delete Cells.ClearFormats
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
'Clears all formatting in entire sheet every time a new cell is selected
'Anytime a cell in column A-Z is selected it will be bold, yellow, outlined, size 14
Const WS_RANGE As String = "A:Z"
If Not Intersect(Target, Me.Range(WS_RANGE)) Is Nothing Then
Selection.Font.Bold = True
Selection.Borders.Weight = xlThick
Selection.Interior.Color = 65535
Selection.Font.Size = 14