If you’re getting the language selection and payment screens, do you have the full, paid, version of WD or do you have a trial version?
It could be that the 30 day trail period is up?
If you have paid for WD already then it could be that the settings have been lost and it’s not recognising that you have paid, in which case have a look in the WD folder for a file called WDISPLAY.INI and open it in something like NotePad to check that there’s something in there.
It could be corrupt in which case run through this FAQ to recover the settings: Recovering Weather Display Configuration
One other thing; when you install the update, make sure ALL Weather Display related programs are shut down, the likes of Realtime FTP, Webcamcapture and WD FTP as these can stop the new files from being installed correctly if they are still running. 