Thanks to all who helped, I've finally solved the problem by more luck than science! As GE relies on Internet Explorer, I figured that maybe this could be a cause. To back this theory up there were some websites that wouldn't allow me to enter a log-on name etc (i.e. I couldn't type my details in the boxes). Could this be ActiveX, I tried all sorts of ways to re-install ActiveX, but failed. I grasped the nettle this morning and uninstalled IE9 completely and re-installed it from scratch. It worked! So can only conclude that something had been corrupted in a recent update, but repaired by the new install.
In case it helps anyone else, I'm still running on Firefox as my default browser, but it seems that it is also essential to have a fully working version of IE as well. You are in a virtual loop if some part of IE has a problem because you cannot download another new copy to "repair" the suspect existing installation! As soon as I uninstalled the suspect version, the MS website allowed me to install the new download, and everything noted as previously "odd" started working correctly again! I'm not a software expert, so cannot explain why it should have stopped me selecting 3D within the ShipTrax programme, but happily let me view in 3D by using the GE link as a loader! Everything is fine now, thanks again to those who tried to assist.