I need to remove a large old style wooden sash window and want to fill it in to use as wall space. It is in the front wall of the house. How to I tell if it is weight bearing wall or doesn't it make any difference? And would all I need to do is build a frame and then put studs in?

Firstly a window is never load bearing as the opening would sag or collapse, once you have removed the window you have to frame in the opening using either 2x4 or 2x6. Next you face of on the outside using plywood, face that off with building paper or as I prefer to use -tar paper that is used on your roof as I find it breathes better than building paper. Next follow up with brick on the outside, on the inside you have to put insulation in between each of the studs which are normally on a 16 inch centre. Though that could be changed depending on the width of your opening, once you have the insulation in the wall you now have to put on a layer of 6mm plastic and tape your edges with red tuck tape. Drywall is the next step, if you are still not sure you can Google for information on the web or visit your nearest Homedepot or Lowe's and be sure to make sure the member of staff you talk too knows what the hell he is talking about. Hope this helps you in some way, keep us informed on how you make out.

This is very helpful, but just regular bricks? How do I stick them to the tar paper?

@Daley. 'How do I stick (the bricks) to the tar paper ?'

You are kidding. Right ?