Just FYI. I had same problem so resetting Chrome and deleting the C:/AdwCleaner folder helped get rid of PUP.Optional.Legacy virus. However, in my case, I know where I got this virus. I ran AdwCleaner on my system before installing GOM Player from Gretech Corp and it came out clean. I ran AdwCleaner again right after installing GOM Player and PUP.Optional.Legacy virus turned up. I did run a scan by Malwarebytes (Free) AntiMalware on the .exe file before installing and turned up negative so I went ahead and installed. Anyway, problem solved and GOM Player uninstalled
