Install on Windows
You can get the Windows installer from the download page of the MuseScore website. Click on the link to start the download. Your Internet browser will ask you to confirm that you want to download this file. Click Save File.
When the download finishes, double-click on the file to start the installation. Windows may prompt you with a security window to confirm this before running the software. Click Run to continue, you'll then briefly see
In case you don't see this installer window but something else, it's possible that the .msi extension is not associated with msiexec.exe. Either you can fix the association, or download and use the portable version of MuseScore instead.
Continuing you'll see
If you click Cancel, here or later, you'll see:
If instead you click Next to continue, the setup wizard displays the terms of the free software license.
Read the terms of the license, make sure the box next to "I accept the terms in the License Agreement" is checked, and click Next to continue. Next the installer will ask you to confirm the location in which to install MuseScore.
If you are installing a newer version of MuseScore but still want to keep the old version on your computer, then you should change the folder (note that MuseScore 2 can coexist with MuseScore 1 with no changes needed). Otherwise click Next to continue.
Click Install to continue.
Give the setup wizard a few minutes to install the necessary files and configurations. You'll see
Click Finish to exit the installer. You may delete the installer file you downloaded.
To start MuseScore, from the menu, select Start→All Programs→MuseScore 2→MuseScore 2.
You can uninstall MuseScore from the menu by selecting Start→All Programs→MuseScore 2→Uninstall MuseScore; or via Windows' Control Panel. Note that this will not remove your scores nor your MuseScore settings.
On Windows XP and Vista, the installer might be blocked by the system. If you don't manage to install MuseScore, right click the downloaded file and click Properties. If there is a message "This file came from another computer and might be blocked to help protect this computer", click on "Unblock", "OK" and double click on the downloaded file again.