"Full configuration of the system and browser install"? Well, I'm not a computer expert. It's the latest version of Opera, I had installed it one week ago, under Windows 7 Professional.
Open your browser's "About" (in the menu) - you'll see the info (not sure if it's copypastable).
Next. Are you the only user of your workstation? Is your operating system genuine and up-to-date?
What "hardcore" programs do you have "hot-wired"? Means antimalware and cleaning software, other stuff that can control your system.
Did you use Opera browser before?
When you installed the current (problematic) one? What was the source? Was the install regular or did you change folder(s) and/or other settings when installing?
What are the other browsers you use there now? (In case of certain "cloggy system" issues or alike.)