Honestly dude IMO if it takes more than an hour to try and get a virus off, back up what you can and restore it. Dicking around to much is doing nothing but wasting your time and the customers.
Anyways Im not sure if you just tried a virus scan saw what it was and then tried to remove it, if not use Malwarebytes see if something else is hiding in there… If you have bootable software such as avast/norton/Eset or Dr Webb that will do a bootable scan than give those a try.
Sometimes dude certain viruses get so embedded its nearly impossible to get rid of them without spending hours on it. IMO it just wouldent be worht it to me.