Like others to load your web file took an eternity on my old machine. I wouldn't create a site with that many pages either, but that said there's very little content at present on your site, so what's slowing it to crawl. I noticed the following:

You have a header advert 'Amazon K2 Teaching Resources' on almost all pages. These are not repeating although they are on most pages. They also are set to 'Regenerate placeholder image automatically'. The same is true for the Disneyland official album.

I wondered if the non repeating was an issue so created a test site with 124 pages, pasted in both adverts but changed the fill to flat fill rather than an image. I also unchecked the 'Regenerate placeholder image automatically'. Then proceeded to 'Copy on All Pages'. Closed the web file. Reopened & it opened smartly with little delay. I then deleted these Ads from all pages and re-pasted the original Ads with the 'Regenerate placeholder image automatically' set and set to repeat on all pages. Saved & closed. Reopened again smartly without issue.

Finally I deleted all the ads from all the pages again and this time pasted the ads as a non repeating object on each page (Ctrl+Shift+V) on 60 of the pages (couldn't do any more of this boring repetition!), saved closed and reopened and again fairly smartish.

So in conclusion I believe your .web file has become corrupted. Sen it to Magix support and see if they can locate the problem.