Build Trial Evaluation

I want to post a 30 day trial version of one of our locked Workbooks on our server for users to download. I want to keep this trial version on our site without having to re-compile it every time I want to extend the expiration date. Is there any simple method or code to embed in the locked workbook that triggers day 1 of 30 when the workbook is first opened and the 30 day count begins from there?

Also, is there a .sil file for the nag screen and where to edit the nag screen?

Sure, open the .sil language files in Notepad to change texts used by the nag message.
EXE files themselves don’t have built-in expiration dates: it’s the activation key that can have an expiration date.
You could for instance create a form on your website that asks for the user’s email. Then, a PHP script would send an email with the download link to the EXE and an activation key (with an expiration date of 30 days). The user downloads the EXE, runs it and enters the activation key received. He can then run the workbook for 30 days.

What is the nag message sil file named? Can graphics be added to the nag screen, if so how/where? If I send an activation key with an expiration date of 30 days when does day 1 start?

The nag message’s text is defined in the .SIL language file. Just open the default English.sil and search for trial.
No, graphics can’t be added but we’ll see whether this can be done in the future. The trial period starts when the end user enters their activation key.