Try to reinstall the game not to the Programm (x86) folder and do a exclude in your anti virus.
Which Anti Virus software are you using?
Windows 10 basically come with Windows security, that's my only protection on the laptop.
Reinstalled the game(not in x86 folder) now i don't get anymore the invalid acces memory message , but i get the message "Failed to download the file"
EDIT:// I solved my problem, there's my solution:
1. Delete the folder "_download" and "_BetaPatch" from the game client folder and keeping switched off the antivirus restart the launcher.
I hope it works for new members which encounters this problem!