It appears that WDP365 auto saves the file when you try to close the program after an error -- which is like suicide for the file. I would like to request a more robust file recovery capability in this program. Seems like a good investment in your reputation.
you can use task manager to close the file without any of the termination routines - right click task bar for task manager, select the xara task and click end task button

can't help you with the web design issues, but hopefully someone else will

however in general, if you are getting blue screens something may be wrong with your system; personally I get less errors with win 10 than before, one of the reasons I like it [assuming it's set up right, and that can take a bit of doing I will admit if you don't want cortana and the like; best to have win 10 pro maybe]