"TODAY()" function and viewing or printing original date

Insert index column for invoices and for each invoice issue you can use index with vlookup function. if D1 is the index cell in invoice sheet and A1:B2500 is the range of index and invoice date repectively.
For example
=vlookup(D2,A2:B4,2,false)

I probably should have attached this in the first place....
Attached is the invoice I am using with the "today()" function.
I am not quite understanding the last reply from ASMOGHAL. I guess I am not that knowledgable in formulas and such. I definately do not understand the vlookup deal. Is this something that should be inserted in all my invoices or is it a way to retrieve my old invoice dates?
I'm confused, please bear with me.

Originally Posted by shg

Rather than using a formula to enter the date on a new invoice, you can enter it as a literal value using the keyboard shortcut Ctrl+;

Using ctrl+ in a cell opens an "insert" box. How does that help enter a date?

Originally Posted by martindwilson

ctrl ;
the + is conventionaly used to show use both keys together like ctrl+alt+delete

Oh boy! Now I feel dumb.... I totally blew that one. Thanks for pointing that out.
Yes that works great!
Thank you.
NOW I need to know if there is a way to print out or view my OLD invoices that used the "today()" function....
when I open the file it automatically inserts TODAY's date instead of leaving the original date it was saved.

Originally Posted by shg

Press and hold the Ctrl key, then press semicolon.

Yes..... oops....
Thanks!
That works great!

Originally Posted by shg

No; you're going to have to correct the date manually, based on the previous file save date, or whatever other data you can resurrect.

I was afraid you would say that!
I have pulled out the "today()" function and will enter it as a literal value using the ctrl and the semicolon key.
Thanks for your quick responses!!
All very helpful!