Rebuilding old software
The Access database, the spreadsheet with 18 tabs, the PHP 5 site nobody wants to touch. I rebuild them and bring the data across.
When it's time
The software still works, but only on one computer running Windows 7. Whoever wrote it no longer answers. The spreadsheet has macros nobody dares touch, or the site runs on a PHP version the hosting company is about to drop.
How I rebuild it
I start from the old software: I open it, read the tables, formulas and macros, and write down what it really does, including the rules nobody remembers any more. I can also read Access databases (.mdb and .accdb) without needing Access. Then I rebuild it as a web app, with the old one still running until the new one is ready.
The data comes along
For my CRM I wrote a script that imports the old data and can be run again without creating duplicates, so the last import happens on switchover day, with that morning's data. The original spreadsheet had 18 tabs, and it stays available in an archive with its original formulas.
Problems I often solve
A Microsoft Access alternative: your database as a web app
The Access database that runs on one office PC, with forms built years ago and macros nobody touches. I rebuild it as a web app: it opens in the browser, on Macs and phones too, and your data comes along.
Rebuilding a Visual Basic 6 or Delphi program
The business program that only starts on the old Windows 7 PC, needs a runtime installed by hand and has nobody left to update it. I rebuild it as a web app and bring the data across, with the old one running until the new one is ready.
Moving off FileMaker to a custom web app
The FileMaker database that has run the office for years, with layouts built by someone who has since left and a licence to renew for every user. I rebuild it as a web app that opens in any browser, and your data comes along.