Usually, to install ADB and Fastboot you have to download and setup the Android SDK, which is an extra-large file (more than 425MB download for full Android SDK). However, if you just want to install ADB and Fastboot, XDA forum member shimp208 has created a Minimal ADB and Fastboot. This windows installer will install the latest version of ADB and Fastboot for you quickly and easily. The total installation of Minimal ADB and Fastboot is around 2 MB in size making it very lightweight. Installation Instruction
Connect your Android phone or tablet to your PC via a USB cable (keep in mind that you must enable ADB debugging under Developer Options)
Download the Minimal ADB and Fastboot setup.exe (download link below this post) and follow the installation instruction.
Once installation completed, navigate to the folder where you have installed the Minimal ADB and Fastboot (for example C:\Program files)
Hold down the Shift button and right click inside the directory you installed the files to and select the “Open Command Window Here” option.
You should now see a command window open, with the command window open you can now issue ADB and Fastboot commands to your device. Download Minimal ADB and Fastboot for Windows from XDA.