Times When It May Be OK to Use a Similar or Identical Name
There are a few situations in which it may be okay to use a name that is already in existence -- just be sure that the name your are using is not famous! For example, if the name that you want to use is already being used by another company, but the other company sells a drastically different product than you plan on selling, then you may be able to move forward with using your chosen name. In addition, geographic location can be another factor that can let you use an identical name. If the business that already has your name is far away and serves only a small population, this makes it safer for you to use the name.
The key question that you have to answer is, "is it likely that a customer would be confused about the origins of the product or service if I used the same, or a similar name." For example, suppose that a business called "X-Y-Z" already exists and sells candy in Oregon. If you want to open a business called "X-Y-Z" that repaired computers, it would probably be pretty safe. If you wanted to open your business in Florida, it would be even safer.
Starting Your Business: Business Name Availability - FindLaw