Multiple Upgrade Problems

[Cathus3]

I'm having loads of issues upgrading.

I tried upgrading 1.2.16 to 1.30. It ran and then I couldn't access website or admin, just got a blank page. As I couldn't access admin, I couldn't do a restore from the backup.

After hours of trying I decided to just delete the site, load 1.4.0 and then import my php database backup. It was too large to upload so I've spent all day loading individual tables.

Lots of issues now but here are two. My layouts have suddenly disappeared. All page templates appear in the screen grab. The Novator template appears to be missing though it is referenced in my php layouts table

I can't turn blocks on and off, the blue ON switch is kind of greyed and when I mouseover it a red NO ENTRY sign pops up.

I may have overwritten some new 1.4.0 tables when importing my old website tables

what is the best way to get my site working again, preferably with 1.4.0 or should  just delete everything and load a 1.2.16 site which worked fine?

[Cathus3]

screenshots re above

[Basara]

Hello.
When a blank page occurs, you should still be able to see the errors in your AbanteCart error log file. You can view this log file (/system/logs/error.txt) or server error log via your hosting panel's file manager, which will help you identify the issue. The most common causes are outdated extensions, custom code or an incompatible PHP version.

Additionally, please note that your 1.2.16 database will not work with the 1.4.0 code.