Search your computer for limewire. See what results you get. See if there is any other program listed other than LW 5. You might need to go to the program file's details window to seek information about it.

You should certainly know if LW 5 is opening because it looks totally different to LW 4.

You could possibly try rebooting & repeating the process without opening LW until the final step. Perhaps elements of LW 4 are still stuck in memory or haven't completely closed whilst you are attempting to uninstall & reinstall. Also, this time, delete the LW preferences folder before doing this process.

I am highly surprised CCleaner did not pick up on the issue. CC is usually highly reliable for finding these kinds of issues 'if' there are older elements of programs still lingering on the system.

After installing LW 5, you will need to re-add it to your firewall exceptions.