Conventional operating systems can range from absolutely no cost (minus that of downloading and burning to a CD) to several thousand dollars for high-end servers and supercomputers. Custom-made...
It depends on what material you want to use. $1 to $5 per square foot of wall space and $300 to $950 each soundproof windows. This link should help you. See related links
Depends on the size of the room. A typical 12 x 12 room can be given 1 coat with a gallon of paint. A gallon of quality latex paint will cost you from $20 to $30.