You can get the file toeflpracticetest_setup.exe from the link above. It's a good experience to check the file for malware. So, use your antivirus program or try a free one – AVG AntiVirus Free.
Download the 5 MB and start the installation by double-clicking on the file and following the steps of the setup process.
You won't face problems with uninstalling the program. Click Start and then Control Panel. Choose Free TOEFL Practice Test and press Uninstall.