Sometimes yes, sometimes no. Making something shareware doesn't automatically remove copyright restrictions on it, it just gives people a license to use and share it as they like. Any "about" file or "readme" or similar documentation will spell out the creator's expectations.
Shareware
Sure. The copyright owner of something can do with it as he or she pleases, and if that means giving copies away for free, that's fine.
Nearly all of it. Shareware and Freeware would be exceptions.
It is usually called "open source" software.
The majority of shareware and freeware programs are still protected by copyright, but the rightsholder has attached a broad license allowing free distribution, sometimes with certain limitations. The rightsholder may choose to reserve certain rights, such as the right to alter the program or create derivative works.
Commercial software, shareware, any number of things.
It depends on the license provided by the copyright holder. Many apps distributed as "shareware" still request that users download it directly from the original source, as a method of tracking.
Shareware can be distributed without a license from the copyright holder. Works given Creative Commons licenses can also be shared, and in some cases even altered, without specific permission from the creator, depending on the type of license.
Software is one of the few things protected by both copyright law and patent law. Unless the software is freeware or shareware, or you have a license to copy it, you are limited to one installation.
Not unless it is specifically prohibited by the game's manufacturer. Shareware users are generally encouraged to give copies to others. However, if he has given a copy to his friend, George obviously likes the game, and he is under a moral obligation to contribute some money to the makers.
Shareware is free software that may be distributed after which a fee may be requested for continued use.
I usually download shareware from the website below. More than 20000 sharewares are on the website.