My Windows Firewall is 100% disabled, and my Kaspersky runs as if it weren't there at all; I make all the decisions, it does not. 'World of Tanks has stopped working.' Is all I get for the crashing. The invalid key error is a pain, but not as annoying as leaving the bot online while im at school and coming back to find 1200XP in return for leaving my computer on 9 hours more than it had to be.
TLDR: No firewall, and the Key problem is server-side not client-side. MAIN PROBLEM is the crashing. Seriously, I'd pay you to fix this.