If two people are on a home title, and one party, Party A wants to sell, and Party B does not, can Party A force Party B to move out?

The answer is almost certainly "yes."  In most states there is a court proceeding that will allow a co-owner to force a sale of property where the joint owners cannot agree on a resolution between or among themselves.  This proceedings is ordinarily referred to as a "Sale for Division" proceeding.  A co-owner can file a petition with the court alleging that the co-owners together own property; that one wants to sell and that another does not.  The request to the court is that an order be entered to sell the property by public auction.  Either party could bid on the property at the sale.  The court will ordinarily keep a commission (usually 10%) for its time and services in arranging the sale.  I can't tell from your question whether the case at hand has reached that point.  Party A "serving papers" may signify that such a proceedings has already begun.  I recommend that you seek the advice and assistance of a good real estate lawyer in your area to help guide you to a reasonable resolution.  A public auction will often not bring the best results, but it would solve the problem -- which appears to be more personal than legal.