Security Error Message

[SwAGMAN]

Well this must be a record - I downloaded the trial version of VS9 and was very happy with it so decided to upgrade over the internet to the full version. I did that and downloaded the HDV and a couple of other modules from the smart download section and now I get the following message when I attempt to open the program.

"The Security information is invalid or has been modified, the programme will be terminated"

I've had the full version less than 2 hours and it's unusable . Anyway looking at other posts I get the impression I'll have to uninstall the whole lot and redownload the trial version then use the serial number I already have to upgrade to the full version. Is that the only option I have or does anyone know of anything else I can try?

Cheers

Steve
XP Home SP2