You can get the file soundboostersetup.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 – Avira Free Antivirus. Run the file after getting 6.5 MB and follow the setup instructions.
You can uninstall Letasoft Sound Booster without any problems. Click Start and then Control Panel. Choose the program you need to remove and press Uninstall.