That's some ancient code there, Norman
Did you check out the link Eric gave you?:

Switching to a modern Doctype, along with up to date character encoding might help.

One other consideration (for any website) is file size. You've got some huge images that are being resized by the browser, which means they're very slow to load – even on a fast connection. On a slow connection, viewers will see nothing, followed by 'slices' of the image loading in one at a time. For example, the Skoda Yeti pic:
2,145px × 1,627px (scaled to 460px × 300px)
That one image 'weighs' more than many entire websites (4 mb vs 1-2 mb avg.).
You should change that to the smaller size in an image editing program before upload.

Maybe consider a gallery type site with a lightbox to display your car photos?

I wanted to know what the page looked like before direct ftp because I see content.

I wrote that stuff about 20 years ago. That Yeti image that "paintbrush" is talking about is 0.4 Mbytes not 4.0.
On my computer not one of those images takes more than 0.25 secs. to load. What speed is your internet access in your area. Mine is quite slow here at 38Mb/s.

Anyway none of that would make any difference to whether a file loads properly or not.

You say that 5 out of 30 times it loads correct ??

Um, nothing wrong with the program and I wouldn't think anything wrong with your settings. Either it works, or not. The only reason for it to 'sporadically' work that I can think of is if there is noise on your internet connection. Noise can be caused by bad equipment on either your end or the server or anywhere in between. Can also be caused by many other things such as new construction. Anyone put up new high power lines in your area? Just guessing here, but if it works once then a bad internet connection is my guess.

Now, you say it 'always' works with your old XP computer? Well, that would in my opinion narrow it down to a problem on your 'new' computer. Either you have interference coming in somewhere that it is picking up, or perhaps just a bad net board. If you are on a desktop try finding someone working with computers in your area and see if they'll loan you a net board you can swap in. Do you use a router in your home? Could be a bad router. Still guessing...just some things to think about.

If .html files are uploaded correctly on your new machine, and any other files except .htm ones, I find it hard to think that the internet connection is to blame (assuming that your XP machine is on the same connection). The hardware - possibly. If you know someone with the same system setup as yours, maybe they will let you try uploading from their machine.

Regarding the yeti image, yes, the file size is somewhat above 0.4MB, but the image size is huge. I've attached a copy in the right size, and as you will see, the file size is much, much smaller. I kept the proportions, so the width is 460px, but the height is somewhat more than 300px. I don't think you should squash it down to 300px height, rather crop it a bit.

Addendum: Have you tried uploading the htm files to a different server? If you don't have any other servers to test it on, maybe the CC support can give you some temporary access somewhere.

My 'premium' plan provides a bit over 18 Mbps; 3 X the average plan speed.
If 38Mbps is slow in your area, then I guess you don't have to worry about huge images.

He can try uploading to his S-Drive account and see if the .htm files upload.

I have since tried IPswitch client and again get file shortening of html and htm files. Each file is shortened to the same length each time. e.g. a 22k file will always be shortened to 4k but sometimes will be uploaded complete. The big jpg files seem to be untouched. This is on Windows 8.1.
Have you not seen any other 8.1 users with this problem. Searching around Windows 8.1 does seem to have a problem with ftp but usually it is in the connection not file shortening.
I would love to get an answer to this problem and then purchase Coffee Cup.
All this time my old Terrapin client on Windows XP works perfectly on the same connection.

I have not found an ftp client that works on Windows 8.1 and believe it is a problem with one of the files used by IE 11. Does any one know that there is no problem with Windows 10 and the change to Edge?