@pedro78 Check on 'about Opera' to make sure you have the latest stable version 53.0.2907.99. Update if not. This was my problem.
Else, download another browser eg Firefox and use it for logging in to online banking.
64 on 64 should work better.
About the other suggestion, I've read many different opinions, but didn't tested myself.
Windows 10 (x64) | Anniversary Update
Opera Stable · Beta · Developer
Test profile | Back up Linux · Mac · Win