A preset or editing applied to all the photos on my computer

So let me dissect your post and try to understand better your problems-

I installed lightroom classic and added 2 photos

So a fresh install, starting with a totally new Catalog and 2 images imported, correct?

...edited them it was all fine but the next day when I turned my computer on I saw the last editing or a preset applied to all the photos on my computer,

Well that sounds correct when viewing only the 2 photos IN Lightroom-Classic. But as described by @Sean McCormack  LrC will NOT change all photos in your computer.

when I click and open a photo it is the original version

How do you "open"? - In Lightroom-Classic, or some other viewing App?

but after 1 or 2 second it changes and it turns to an edited version.

And was that in Lightroom-Classic, or some other viewing App?

I even deleted lightroom and everything related to the app but it didn't work

What "didn't work"?

and I even copied the photos to another computer and the exact same thing happened Photos just change.

Change how?

And was that in Lightroom-Classic, or some other viewing App?

And do you have a calibrated monitor?

Post a screen-clip of the page you see from the LrC MENU: Help > System Info...

And a screen-clip that might show the "change" you see.

Or this 2010 article might explain-

Why do I see my images change after they are imported into Lightroom? | Laura Shoe's Lightroom Training, Tutorials and Tips

Lightroom-Classic never changes the image data of your files on the hard-drive.

LrC creates its own preview to dislpay in the catalog, and its appearance can be altered by any Profiles or Develop Presets that might be applied in the import process. But it is only the 'Appearance' of the image in LrC! You can change that in many ways as you choose.

Lightroom can only work on photos that are imported to it. It can't affect any other photos on your computer.