Usually the game folder is somewhere Windows protects. Move it out of Program Files to somewhere like C:\Games and try again. If your antivirus is quarantining files, add the folder to its exclusions. More on the Support page.

On Intel laptops the launcher applies a graphics fix by itself, so most of those crashes are already handled. If it still crashes, open a ticket with the name of your antivirus and any error text; anti-cheat and antivirus software interact badly often enough that it is the first thing worth checking.

Yes, on every connection. It is why an old client is refused rather than let in. What it means for you is on the Rules & Policies page.