Droid4X is a free Android "simulator" for Windows.
Installing the program takes a while, so patience is essential. The download may be a tiny 2.5MB, but the rest of the package - including VirtualBox and a virtual machine - will eventually take almost a gigabyte of drive space, and the setup process doesn't seem optimised for speed. Just get on with something else and it'll complete eventually.
On launch Android 4.2.2 appeared in a 1280x720 resolution window. There are very few apps installed by default, but as you get the Play Store that doesn't matter very much (or you can install apps by dragging and dropping APKs from the desktop).
A left-hand toolbar gives access to various features. You can set up the program to use the keyboard as a controller (or your phone, if you install another package). There's an option to share folders between the PC host and your Android host. You can simulate a GPS location, take a screenshot, "shake" the device with a click, adjust the screen resolution and more.
Less obvious features include a shared keyboard (Ctrl+C in one environment, Ctrl+V in another), while in theory you can zoom in and out by holding Ctrl/ CMD and spinning your mouse wheel (although this didn't always work for us).
Droid4X had some odd issues for us, including YouTube failing to display videos unless we ran them full-screen. But most apps ran without problems, performance was good, and on balance it's a capable tool.