Can't enter serial number

I have the trial version. When I started it today I got the message:
“Beta Expired
This Scrivener beta expired on Monday 7 November 2011. Please download an updated version from the [Scrivener for Windows website]”

I did so, but whether I click on the link [Scrivener for Windows website] or click OK or close this dialogue box nothing happens - I can’t enter my serial number because no other dialogue box opens, Scrivener doesn’t open, I can’t get past this “Beta Expired” message.

I tried re-installing the trial but same problem.

You should be able to just click “OK” to dismiss the message and close Scrivener, but if that’s not working you can force-quit through Task Manager. You’ll need to uninstall that beta and download the 1.0 trial from here. This is a true trial version rather than a beta, so it has no set expiration date but will give you 30 non-consecutive days of use before you need to register it. At any time you can enter a license number either by clicking “Enter Lincece…” in that trial window or by using Help > Register… when you have a project open.