Hi! I am sorry you are having problems. Are you using open beta or stable release? In the latest open beta there are some issues that could cause a crash to desktop, I suggest you look into the Bugs & Problems forum section to see if any of them might be what you are experiencing. I should add that frequent crash to desktop or locking might be another issue, like for example your CPU or GPU overheating. The Viggen is slightly more resource-hungry than other modules so it have been affected by this before while other module has worked better. Hope we can sort your problems out.