Many modern households have more than one computer. Often, each computer has a different owner. Some people, however, use more than one computer- and they coexist on top of the same desk.
If you're one of these multiple computer users, you may have two desktop units, or perhaps a desktop and a laptop or two. Using them all at once leads to problems, with a keyboard or two, perhaps a trackpad and even multiple mice to juggle. That gets very confusing.
You could get a hardware KVM switch. This lets you use one keyboard and mouse on multiple machines. However, those are expensive and a bit clunky.
A software developer at Microsoft had a similar frustration. So he created a solution. It's called Mouse Without Borders, and it's a free download.
Mouse Without Borders lets you easily share one computer's keyboard and mouse with up to 3 other Windows computers. You don't need a hardware switch, and setup isn't complicated. Just be sure all the computers are on the same network.
The download goes beyond clicking solutions. It also allows you to drag and drop files between computers. It additionally supports copy and paste functions and other cool features.
(Download link is at the bottom of the post where it says Download Now)