Added clarifying steps to Windows section of build guide

diff --git a/BUILD_GUIDE.md b/BUILD_GUIDE.md
index e8b242e4e3ccb8a46899fdfa6add76fe3b7ef671..22df53c30d1f5c896e0e72df6172a93584678310 100644 (file)
--- a/BUILD_GUIDE.md
+++ b/BUILD_GUIDE.md
@@ -3,11 +3,13 @@
 ## Build Environment Setup
 
 ### Windows
-1. Install [MHV AVR Tools](https://infernoembedded.com/sites/default/files/project/MHV_AVR_Tools_20131101.exe). Disable smatch, but **be sure to leave the option to add the tools to the PATH checked**.
-2. Install [MinGW](https://sourceforge.net/projects/mingw/files/Installer/mingw-get-setup.exe/download). During installation, uncheck the option to install a graphical user interface. **DO NOT change the default installation folder.** The scripts depend on the default location.
-3. Clone this repository. [This link will download it as a zip file, which you'll need to extract.](https://github.com/jackhumbert/qmk_firmware/archive/master.zip) Open the extracted folder in Windows Explorer.
-4. Right-click on the 1-setup-path-win batch script, select "Run as administrator", and accept the User Account Control prompt. Press the spacebar to dismiss the success message in the command prompt that pops up.
-5. Right-click on the 2-setup-environment-win batch script, select "Run as administrator", and accept the User Account Control prompt. This part may take a couple of minutes, and you'll need to approve a driver installation, but once it finishes, your environment is complete!
+1. If you have ever installed WinAVR, uninstall it.
+2. Install [MHV AVR Tools](https://infernoembedded.com/sites/default/files/project/MHV_AVR_Tools_20131101.exe). Disable smatch, but **be sure to leave the option to add the tools to the PATH checked**.
+3. Install [MinGW](https://sourceforge.net/projects/mingw/files/Installer/mingw-get-setup.exe/download). During installation, uncheck the option to install a graphical user interface. **DO NOT change the default installation folder.** The scripts depend on the default location.
+4. Clone this repository. [This link will download it as a zip file, which you'll need to extract.](https://github.com/jackhumbert/qmk_firmware/archive/master.zip) Open the extracted folder in Windows Explorer.
+5. Right-click on the 1-setup-path-win batch script, select "Run as administrator", and accept the User Account Control prompt. Press the spacebar to dismiss the success message in the command prompt that pops up.
+6. Right-click on the 2-setup-environment-win batch script, select "Run as administrator", and accept the User Account Control prompt. This part may take a couple of minutes, and you'll need to approve a driver installation, but once it finishes, your environment is complete!
+7. Future build commands should be run from the standard Windows command prompt, which you can find by searching for "command prompt" from the start menu or start screen. Ignore the "MHV AVR Shell".
 
 ### Mac
 If you're using [homebrew,](http://brew.sh/) you can use the following commands: