Is it common that a site built in SD3 is all messed up in SD4 when it is opened??? It doesn't look good at any break point. Sorry if this is asked somewhere else.

Well there is normally a lot of work to do with changing things from rows columns etc and it has always been my advice to others is to start again from scratch, which isn't so big a task as it might first seem because you will have most of the content images etc so just a matter mostly of copy and paste

Believe me it will be quicker and less stressful to do it that way

If the site in question was based on something built with a yet earlier version (like RBB, RFF or RSD2.5), it might still have the rows and columns. From SD3.0 onwards there shouldn't really be any problem opening and editing it in version 4.0, as 3.0 didn't use the rows and columns any more.
If you have the 3.0 version of your site online, please let us have the URL, then we could check how it has been built and give you more precise advice.
AND, if you still have a copy of the original SD3 source file, keep it, for safety!

Thank you Wayan & Inger, The site is http://www.Texaslumens.com There is a chance I built the site with a late 2.xxx version but I honestly can't recall and I thought it was 3.5... but sometimes my head plays dirty tricks on me!!!
The site is simple so perhaps just re-building it would be best.

Thanks Again. Dan

Well the first thing I would say is that the site you mention is all over the place on my phone I am not in the office yet but it looks to me like the lower viewports sent working a d displaying properly even on the original site

I can see that your site was built with RSD 2.5-2349 (the last RSD2.5 was build 2425). I'd recommend that you do what Wayan suggested, start from scratch in the latest SD.

It is, of course, also possible to convert the site, but that has to be done manually, and I honestly don't recommend it (I have converted about 20 sites, and it is not exactly a pleasure).

the site is originally SD2.5 which uses rows and columns.
you also need to consider whilst you are working on it, to make it https, to prevent all those "site is not secure" warnings
.
As I previously mentioned a start from new would, in my opinion, be easier, and one can take that opportunity to also tweak it a little, fresh images, fresh content, not much, but search engines like fresh relevant and authoritative content a lot on a regular basis

by the way on my laptop everything is in place and looks good, so we don't know without seeing the project file, what's going on within the project as far as breakpoints are concerned, but that may turn out to be irrelevant if a new build is made.

Thanks Wayan & Inger ... I'll just re-build it. I sure thought it was built in 3.5 so that is 99% of the problem I suspect.
THANKS AGAIN!!! Dan