Website formatting changed despite files remaining the same

I had originally created a website using DP7 in 2012 and had exported it to two different hosting services during the course of the last few years. I now need to upload the original files to a new hosting firm, but when I run a web preview on my current DP 365 version the formatting changes completely regardless of which browser I choose. The text is 3x the original point size and everything is underlined, i.e., a complete mess.
These files had never been changed but had been moved from the original pc and, of course opened in a different version of Xara. Maybe I should try installing the old DP7 and see what happens?

Check your new XWDP application is fully installed by running is as Run as administrator the one time.

If still misbehaving,, open a new Text Area and type in some text. This should be Normal Text style.
If it is the same funny, change this block of text to what it should be.
Highlight it, right-click and pick Update 'Normal' to match.

This will reset your entire document.

If all else fails, upload your design file here for a look.

Final point, I would re-install your version 7 regardless. It will come in handy.

Acorn

I tried running as an administrator as you suggested and text and formatting appeared normal when previewed! I am having trouble with the links working in web preview mode. Then I installed previous version, but same thing. As I needed to make several changes to the content anyway, I am going to start a new website from scratch using the 365 (latest) version, as I think some of the files had got corrupted. Thanks for your suggestion anyway which certainly helped.