Jaycat
Firstly, Welcome to the Chandoo.org Forums
There are a number of ways to see which cell is selected
1. The Cells border changes (as you say this isn't working)
2. The cells color will change to a shade if you have a number of cells selected
3. The Upper and Left Headings (A, B, C..., 1, 2, 3...) will change colro
4. The Name Box, Just above A1 will show you the co-ordinates of the current cell or range
I would look at checking the Excel installation.
A. Firstly update Excel
Instructions here:
http://www.update.microsoft.com/windowsupdate/v6/thanks.aspx?ln=en&&thankspage=5
B. Repair Installation
Goto the Control Panel, Programs and Features,
scroll down and find Microsoft Office and select it
Select Change at the top
When the Microsoft office window pops up select Repair
If the above doesn't work, I'd uninstall and re-install