That is the kind of thing that can only be answered with an on-site inspection of the home by a qualified individual. Having said that, I will attempt to explain the criteria that make a wall a “bearing wall” as opposed to a non-bearing wall.
When a house is designed, there are loads that have to be accounted for due to the weight of the structure itself and from the weight of the occupants and furniture. The weight of the structure itself is called the “dead” load since it is coming from the static, non-movable components that make up the structure of the house itself. The weight, or load, from the people and furniture and also from outside forces such as snow are called live loads. Of course, only the people are actually “live” but I’m sure you get the idea.
In any event, it is the combination of these live and dead loads that have to be accounted for in order for the structure to resist them and to remain intact for a long period of time. We usually use 100 years as the standard to aspire to when we design a structure for human habitation.
In order to accomplish this goal, we design structures based on well-known engineering principles, the scope of which are far beyond the intent of this article. Suffice it to say that the goal is to provide a safe, structurally sound way for the combined loads to make their way from the top of the roof all the way down to the foundation in the ground. The part of the foundation that ultimately transfers these loads into the ground are called Footings. Basically they are concrete slabs of a pre-determined width and thickness that run along the perimeter and inside of the building to support the entire weight of the structure. The soil that the footings sit on is also taken into account when the footings are designed.
As everyone knows, a house is essentially made up of floors, walls, ceilings, and a roof. Most floors, in a wood frame house, are made up of individual beams called joists that are installed parallel to each other. In a typical room with four walls, one end of these beams will sit on top of one wall and the other end will be supported by the opposite wall. The other 2 walls are not supporting the beams and are there to act as room defining partitions. So basically speaking, the two walls that are supporting the opposite ends of the floor joists are bearing walls because they are carrying the weight of the floor. The other two are non-bearing walls. This is an oversimplification and in most cases, it’s more complicated than that. That is why I recommend a qualified person to evaluate your particular situation. Otherwise, a miscalculation can result in disastrous results with a collapse of your structure not being out of the realm of possibility. Good Luck!