catonine, first let me welcome you to iRV2.com. We are glad to have you join us here and we look forward to reading of your adventures and experiences. You will find we are a group of fun loving RVers that like to help each other where we can so if you have a question, just ask. I hope that you will take the opportunity to post an introduction in the New Members Check-In section of the main forum.
Now to your leaking window. You have received good info on how to solve the problem. The window must come out. Cut any sealant around the outside parameter of the framing and wall. Remove the inside screws from he trim ring and with a helper you will need to push and pull till you get it out. You might try using a small pry bar and a putty knife under it to prevent wall damage and go slowly and carefully to get it started. A 5n1 tool (Larger putty knife looking tool) is very useful around RVs. You may find you will have to drive it (5n1) under the outside frame edge all the way around to cut the previous butyl or putty for easier removal without damaging the frame.
Clean off both surfaces and apply new butyl tape to the frame and set it back into place. Center window in hole and reinstall all screws through trim ring loose and tighten using a cross pattern from one side then the other, top then bottom until all are very snug. Be carefully not to break the heads off by over tightening. Trim off the excess butyl. This will continue to ooze out over the next couple of days so don't work about applying any sealant around the frame until this oozing has finished and you have trimmed off the excess again. Clean the parameter of the frame on the outside and apply a clear or matching silicone around the top and two sides of the frame. If you run into any problems, let us know and we can help.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7