Do you want to use one keyboard and mouse over two computer ?

Synergy 

This tool is a very helpful for those of you, who have two computer on your desk and tired of going back and forth to work in each machine. But the two computers should be networked.
you can download Synergy from
http://synergy-foss.org/download/?list

and use this manual for configuration
http://synergy-foss.org/files/user-guide.pdf

Microsoft Garage Mouse without Borders

Mouse without Borders is another tool form Microsoft and easy to implement and you can also copy and drag files/folder from one Pc to another unlike synergy. Try to install and use it you will love it.
http://microsoft.com/en-us/download/details.aspx?id=35460 

Enjoy.