White noise Can't seem to narrow it down

I have never had an issue I couldn’t figure out in cubase until now.
A couple days ago I was listening to a mix when suddenly a very loud white noise started.
Several tracks peaked. I figured it must be a plug in. I bypassed them all one by one.
Finally I got it to stop after bypassing Cubases Ping pong delay.
Later I opened a track that had automation and the noise would not stop until I disabled the automation.
Then another track required that I bypass the waves reverb.
In 16 years I have not had an issue like this one. I do not understand what is going on.
I’m not even convinced it’s one of my plug ins. Let along the cubase plugins.
I’m hoping someone else has experienced this and maybe there is a simple fix.
Please excuse my ignorance if my post etiquette is not up to par, this is my first ever forum post.
Thanks -John

Windows 7 ultimate
cubase pro 9.5
intel core i5 3330 cpu @3ghz
16 gig ram
64 bit

Hi and welcome,

Make sure you have no plug-in in Trial/Demo license in use, please.