You need to follow the same procedures for the eviction of someone renting a room as for someone renting an apartment or house. You need to serve the 72 hour notice of nonpayment of rent on the tenant in person or by first class mail (not certified) (See ORS 90.155(1). If the notice is served by mail, you need to add three days to the 72 hour notice (See ORS 90.155(2). You then have to attach a copy of the notice that you served on her to the eviction complaint that the court clerk will provide you with. The eviction complaint has to be served by someone other than you or your wife. I suggest that you have a process server do it. They will do it the right way and for a minimal fee. Then you need to show up in court on the first appearance date. If she doesn't show up, the judge will enter a judgment of eviction. Small claims court will be your recourse for collecting what she owes you.