Can't get program to install

[GeminiZi]

Hi, I had norton personal firewall installed in my computer, after uninstalling it, I restarted the computer. Now I want to install norton personal firewall back, but it's telling me that I must restart my computer to complete an earlier uninstallation. I've done that many times, but I'm still getting the same error message. Any suggestions to fix this problem? Thank you.