Hello @tiny450 and Welcome to the Webroot Community!

WSA does support Vista!

PC & Mac Requirements

Microsoft Windows XP 32- and 64-bit SP2, SP3 

Windows Vista 32-bit (all Editions), Windows Vista SP1, SP2 32- and 64-bit (all Editions)

Windows 7 32- and 64-bit (all Editions), Windows 7 SP1 32- and 64-bit (all Editions)

Windows 8 32- and 64-bit

Windows 8.1 32- and 64-bit

Windows 10 32- and 64-bit

Mac OS X 10.7 (Lion)

Mac OS X 10.8 (Mountain Lion)

OS X 10.9 (Mavericks)

OS X 10.10 (Yosemite)

OS X 10.11 (El Capitan)

macOS 10.12 (Sierra)

macOS 10.13 (High Sierra)

macOS 10.14 (Mojave)

macOS 10.15 (Catalina)

Please follow the steps below closely in terms of installing WSA on the target system/machine!
 

• Make sure you have a copy of your 20 Character Alphanumeric Keycode! Example: SA69-AAAA-A783-DE78-XXXX
• Be sure you have or add your Keycode to your Online Console: Webroot SecureAnywhere Online Console
• KEEP the computer online during the install to make sure it works correctly
• Download a Copy Here (Best Buy Geek Squad Subscription PC users click HERE).
• Install with the new installer, entering your Keycode when prompted to do so in the install process
• Let it finish it's install scan
• Reboot

Thanks,