I do all of my billing on Excel and have a spreadsheet format that I use for keeping track of everything that is done at a clients place, how long each job took, what chemicals and how much was used, and so forth. It automatically calculates the monthly rate plus materials used and at the end of the month I give this information to the client sort of proof of services rendered. This information also automatically generates an invoice sheet. The whole idea is that I want to supply the client with detailed information (no problem) and also generate an invoice, but with little or no additional data entry. But the problem has been with creating an invoice number and an automatic invoice timestamp that doesnt change (non-volatile) with the computer clock. Theres a function that puts a date on the invoice, but its volatile and changes all the time thats obviously no good. And I can create a random number for the invoice, but theres no rhyme or reason to that method. Anyone have any ideas?