@burnout426 My windows version is: Windows 7 Ultimate and here is my sfc /scannow result

@giovanni64 I have to correct myself.
When I try to install Opera_84.0.4316.21_Setup.exe nothing happens and nothing shows up, exactly!

@leocg I cannot install it. Every time I try it ends up with "Opera Installer has stopped working. In other words, Installation is not possible!

@burnout426 My windows version is: Windows 7 Ultimate and here is my sfc /scannow result

@leocg I wish to know why it doesn't work! The latest version is not working too.

@leocg The latest 84 version I've tried but it doesn't work at all.
OK, I will delete those folders you mentioned and just keep the newest and see what happens.

@leocg Thanks a lot so far and here is what I accomplished:
This is the Problem signature from Opera 79.0.4143.22 Setup file:

Problem signature:
  Problem Event Name:	APPCRASH
  Application Name:	Opera_79.0.4143.22_Setup.exe
  Application Version:	79.0.4143.22
  Application Timestamp:	613b575b
  Fault Module Name:	Opera_installer_2202230802334925944.dll
  Fault Module Version:	79.0.4143.22
  Fault Module Timestamp:	613b575b
  Exception Code:	c000001d
  Exception Offset:	000e19a2
  OS Version:	6.1.7601.2.1.0.256.1
  Locale ID:	1033
  Additional Information 1:	0a9e
  Additional Information 2:	0a9e372d3b4ad19135b953a78882e789
  Additional Information 3:	0a9e
  Additional Information 4:	0a9e372d3b4ad19135b953a78882e789

The following Opera Setup EXE files I have tested and are working:

74.0.3911.203/
74.0.3911.218/
74.0.3911.232/
74.0.3911.75/

The listed files below are not working:

75.0.3969.141
76.0.4017.107
79.0.4143.22

@burnout426
Hi, thank you very much for your reply.
I would like to know if this version is a portable one or not: https://ftp.opera.com/pub/opera/desktop/84.0.4316.14/win/

Can you send me a link to download the portable one, please?

It would be good if you let me know how to send screenshots, please.
In the meantime I have donwload the 74.0.3911.203 version and started it to see what happens and I got the exact screenshot as yours but not with the other one.

@leocg Hi, that button with the Options doesn't show up on my computer.
Maybe I need another file?

@leocg
I'm very sorry but I do not understand " Options" I cannot see Options. Where do I find that and how, please?

I double click on it and type run, that's all.

Also before I have tried to install it on a 16 GB USB Stick. No installation possible!

Sorry, nothing came up with the option of selecting a directory and no error was coming up.