OK, make the spreadsheet with the logic.
Save the spreadhseet. NOw make a shortcut to the spreadsheet on your desktop. Now right click over the shortcut and CUT it!
Then press the windows key, and type run<enter>
In the Run window, type shell:startup.
A window will open, paste the shortcut into the folder.
Now restart the computer and test!
I am not going to make the spreadsheet logic for you, as no matter what I post, it will be wrong, and I am not acting as a project manager on this forum (I will help others help themselves, not deploy turn key solutions for free!)
Post back if you get stuck. Post some code and we can help!