Newbie questions should be posted in the newbie section. Especially when they've been responded to once already.
Questions 1, 2, and 4 are asked at least once a week and lately have been asked several times a week. Either check all the posts in the Newbie section or do a search on "Best GPS software" or similar terms.
Question 3: No. Not all GPS units work on battery. In fact, it is mostly the Bluetooth units that use batteries. While some units have batteries sealed inside them (presumably to remember the position of the last location to aid getting a quicker lock), most get their power either from the serial port or USB, depending on the type.