Roblox Studio Crashing With This Script?

Hello!

I would just require a little bit of help please :)

I have a script but it seems to be crashing. There is no error code because my roblox studio crashes ;/

Code:

screen = script.Parent.Decal
while true do
    if game.Workspace.A.Zig.Value == false then
    screen.Texture = "http://www.roblox.com/asset/?id=162925348"
    else    
    if game.Workspace.A.Zig.Value == true then


     screen.Texture = "http://www.roblox.com/asset/?id=162925339"

end 
    end
end 

Yes, I have checked my workspace in the parents.

Please help asap!

Thanks!

Best regards, Nathan.