I am sure you did not understand what the previous posters wrote.
The point is, the forums are not magical wonders where you throw a request to have someone do the project for you and receive a reply with all the work complete.
You need to do the work yourself, and then ask when you are stuck somewhere.
As for building a robot, try Googling (or searching the robotics section of this forum) to get an idea about how to build it. It depends upon what you want it to do. Most hobbyists use what ever they can find.
Controlling it using a computer requires you to have a functional robot, with onboard circuitry and with some sort of computer software written to send the data (that the robot wants to see) through some port.
What I suggest is starting off with some sort of idea, as to what you want the robot to do. Then go on from there.
I am sure you now understand what the previous posters meant.
Hope that helps,
-Omar