That code will work in all versions of Excel from Excel 5 up.
Start Excel and open your workbook. ALT + F11 to open the VBA editor. Insert/Module. Paste the code in there. ALT+F11 to return to Excel. Save and close the workbook. Then open it again and the cell value should have changed.
No probs regarding patience - from the nature of your question I assumed that you would know what to do with the code.