You should be able to call your state and do a registry check for the name. In Canada in Alberta(and I'm presuming across Canada) having your business name registered doesn't mean a thing unless it's a Corporation. With sole proprietorships and partnerships all registering your name does is register it with the gov't, it does not protect against someone taking the name. Becoming a Corporation will protect it. It may be different in the States. There are also 2 different types of registry checks they can do, a simple one which for me is free or a in depth one. I believe the in depth one costs $150 but they said because I'm a sole proprietorship there's no need for me to do it.