Antivirus

magilla said:

... It is on 3 of my 5 computers and Malwarebytes cannot seem to discover it.?????

Try Rkill first before running Malwarebytes.

RKill is a program developed at BleepingComputer.com ... It was created so that we could have an easy to use tool that kills known processes and remove Windows Registry entries that stop a user from using their normal security applications. Simple as that. Nothing fancy. Just kill known malware processes and clean up some Registry keys so that your security programs can do their job.

RKill - What it does and What it Doesn't - A brief introduction to the program - Anti-Virus, Anti-Malware, and Privacy Software

magilla said:

... I finally found the problem was on onedrive there was a uuptoiso Windows iso that bladabindi Backdoor culprit was embedded in....

That just goes to show how thorough Defender is at looking for things. Glad to hear it wasn't anything 'active' on your machines.

...Obviously I need to get rid of these old iso files...

I have a couple of old installers with known PUPs in them that I keep just for testing AV detection of PUA/PUP. I have to jump through loops to stop Defender finding and removing them. I certainly don't want to exclude them as that defeats the purpose of testing, so I have to keep them in a password protected .zip file so that Defender can't scan it.