Just the same here. I am stuck.
My System:
Apple iMac 27" 2,8GHz Intel i7 4Core CPU, 8GB RAM, ATI Radeon HD 4850 512MB VRAM.
Mac OS X 10.6.8 "Snow Leopard".
Parallels Desktop 7.0.15107 Virtual Machine 3GB RAM, 256MB VRAM, 3D acceleration on.
Windows 7 updated.
Firewall on the router eventually everything allowed.
Firewall on Windows I don't know.
I played successfully World Of Tanks till version 7.5, everything OK and very enjoyable.
I updated to World Of Tanks 8.0 and no more luck.
I then deleted everything of 7.5 and reinstall from scratch. No mods, no skins.
WoT launchs OK, I can change modules on every tank and I can chat with my allies. Everything OK.
When I push the "Battle!" button, I see for just 1 second the battle scenery (Himmelsdorf, Mines, ...), then everything disappear. The program is crashed.
I think my tank appears in the battle, as I have the battle report next time I launch the program.
Just the same trouble for training battles too.
I tried to put on minimum all the graphic settings of the game, no luck.
I am not able to play anymore.
World Of Tanks support can't help, and suggest to ask Parallels.
So I am asking to you.
Hope you can!!!