Is there a way within Excel to Auto Generate a new number every time I open a spreadsheet.ie: I made a Purcahse Order template and I would like for Excel to generate a new Purchase Order number whenever I open it up. Can anyone let me know if this is a possibility.

I don't know how to do every time it opens, but you can do this by recording a Macro. If you aren't familiar with Macros, it's a way to record an action or series of actions. Basically, once you've recorded the Macro and told it what to do... you will just have a button in excel to click on every time you want a new invoice number.
I think for what you want, you will have to do in visual basics. I'm not very good at those but office has some step by step instructions. Search "Create a macro by using Microsoft Visual Basic" in HELP. (you will probably have to add the developer tool bar but this is all in step by step)
when it mentions code---
Try to use a code similar to this and paste just before sub: Range("D3").Value = Range("D3").Value + 1
I know you can also insert an object (button) and assign the macro to that button.

This is all above my head though--but maybe it will get you pointed in right direction.
good luck!

This is better done in a database, but is possible in a spreadsheet. But to help you we need to know more about the structure of your template. If it is, in fact a template (xlt file) then you would need to read the number from the last PO you saved since you can't save the template. So more info is necessary.

Thanks for your response. I did find a way to do it in VBE. With the following code:
Sub auto_open()
On Error Go to ErrorCatch
Cells(9, 13) = Cells(9, 13) + 1
If Cells(9, 13) = 10000 Then Cells(9, 13) = 0
ErrorCatch:
End Sub

It works great. I get a new p.o. # every time I open the Purchase order file.