access problems after SSL

Sounds like two classic problems:

a) your browser cookies and/or cache are remembering old things, and need to be cleared
b) your SSL certificate is incorrectly installed, which your hosting company would need to fix.

c) while RARE, the dot-prefix configuration setting might need changing for your specific server's configuration. Should be a last resort, because messing with that can cause problems.

Thank you DrByte for joining.

@kobra
I haven't run the fix, because I have checked it thru phpmyadmin, and regardless of the database import even the fresh reinstall did give the problem.

@DrByte
a) I have cleared the cache and cookies many times
b) That is my suspect as well, and trying to convince host to reinstall
c) What is dot-prefix configuration?

c) Admin->Configuration->Sessions screen.
AGAIN: DO NOT GO CHANGING ANY OF THESE SETTINGS AS EXPERIMENTS. They are not meant to be altered under normal circumstances, and changing them could break your site.

Thank you.

No worry, I have enough headaches to on trying stuff you already warned me about; I just wanted to know.

As a side topic, I apologize again, but would you say this too
http://www.zen-cart.com/showthread.php?201364-no-order-registered-returns-to-step-2-3
has to do with SSL, or server configuration?

Fix your SSL issues first before testing checkout.

Thank you.

The checkout is on another install (v 1.39h), which save a few times has not created access issues.

As far as secure access, if I remember correctly when first accessing a Zen Cart site it is on http, and turns to https on login, and when sensitive data is exchanged right?
Because right now when I access both sites it does it thru https from the start, reverting to http when I navigate the store, in case of customer, and the admin backend sections in case of admin.

Zen Cart only does what you tell it to do.
It uses the URLs you supply in your configure.php files to switch into SSL mode when needed.
To switch successfully, the SSL certificate must be the correct certificate for your website, and browsers must be able to set cookies using domain names that match the SSL certificate and the domain of your website.

If your URLs are wrong, you will obviously have problems.

If your server's SSL is set up incorrectly the obviously SSL won't work correctly, regardless of whether you're using Zen Cart or not.

Removed SSL
I cleared everything, reinstalled once more v1.50, tested, and all seems working fine.

Tomorrow will reinstall SSL, and hope it won't break it again.

Thank you both for the patience so far.

I'll update this as soon as I test it again.

We are making progress.

SSL installed, and I can access admin (had to choose new password), the same as customer on store.

The problem is similar to the issue on the paypal thread (http://www.zen-cart.com/showthread.php?201364-no-order-registered-returns-to-step-2-3)
I am going to update that, if you please can take a look and advise.

Thank you.