Where did NPM go?

Question

Windows

Hello!
I'm learning Laravel from YouTube videos, where I need node.js and write commands like "npm install", "npm run dev" to the console.
In the evenings I worked, I wrote only "npm install" (everything was normal) I turned off the computer, I had to go, today I started again and it does not work, an error occurs 

"npm" is not an internal or external
command, operable program, or batch file.

And then I reinstalled node.js, and now the error is 

internal/modules/cjs/loader.js:638
throw err;
^

Error: Cannot find module 'B:\twophp\OSPanel\modules\php\PHP_7.2\ITproger\node_modules\npm\bin\npm-cli.js'
at Function.Module._resolveFilename (internal/modules/cjs/loader .js:636:15)
at Function.Module._load (internal/modules/cjs/loader.js:562:25)
at Function.Module.runMain (internal/modules/cjs/loader.js:831:12)
at startup (internal/bootstrap/node.js:283:19)
at bootstrapNodeJSCore (internal/bootstrap/node.js:623:3)
internal/modules/cjs/loader.js:638
throw err;
^

Error: Cannot find module 'B:\twophp\OSPanel\modules\php\PHP_7.2\ITproger\node_modules\npm\bin\npm-cli.js'
at Function.Module._resolveFilename (internal/modules/cjs/loader.js:636:15)
at Function.Module._load (internal/modules/cjs/loader.js:562:25)
at Function.Module.runMain (internal /modules/cjs/loader.js:831:12)
at startup (internal/bootstrap/node.js:283:19)
at bootstrapNodeJSCore (internal/bootstrap/node.js:623:3)

Who knows what to do help PJ!
And yes, in the folder where laravel has a folder "node_modules" created at that time after the command "npm install"