My serial number not recognised

I've put in a support ticket for this but I'm guessing the time difference means there's no one around. After problems with the 'save' function on my Storyline (would only 'save as') I decided to do a complete reinstall. All fine, except it won't recognise my serial number to activate. I urgently need to get up and running to redo all the work I lost yesterday. Anybody got any brainwaves as to why? It's installed on the same PC and I have followed all the instructions here http://www.articulate.com/support/kb_article.php?product=st1&id=gdz9t4lj0g7w .

I do have a second install on my laptop but I'd rather work on my PC.