I need help...

I was trying to fix my friend's laptop. the problem with the laptop was that the windows was starting up slowly compared to the earlier.

I thought about the above "Windows Defender".. I downloaded and installed it on the laptop. I made a scan on the laptop. It found one malicious thing (file I guess).. I clicked on the "remove it" button, then restarted the laptop.

But this time the windows did not start up at all. what it does is, that I log in to one of the user's account and that's it. the account is not loading completely, it just freezes, doesn't let me do anything. the icons in the taskbar (bottom right corner of the screen, right next to time) do not even show up, and it just freezes.

When I open the task manager it shows only one application, which is called "Maximizer startup" and its status is "not responding"...

what is going on? help...