Hi Xemem.

Not sure about the other things you added in your post. Is the system working well other than this Flash problem? If so I will the rest there and concentrate on the Flash install problem. If not, perhaps make another thread and detail the other problems?

I would use Adobe's dedicated Flash Player Uninstaller from;

Download that uninstaller file to your Desktop, then run it. it should uninstall all Flash products from the system.

Then I would reboot, (restart), Windows, just to ensure the registry and any system files have been updated.

Next step, back to Adobe to install Flash, from here;

Beware! Look at that web page carefully because Adobe has included an option, (top right of the page), for downloading and installing a McAfee security installer. You may see a different option in your browser. If you don't want that additional utility, remove the tick.

Then download the Flash installer to your Desktop and run it.

See if that works.