Why does Windows 8.1 slow down after loading?

Question

Windows

Suddenly, Windows 8.1 began to slow down very much. Before that, I tried to install Andy (Android emulator for Windows, works through VirtualBox with a wrapper) - I unpacked the image for a long time, I spat and completed the process. The laptop began to slow down a little, and I rebooted it.
Then it happens like this: Windows starts up at normal speed - the login window works fine, without problems and quickly - the desktop opens, and it can stop there. There is a taskbar, icons in place, tray icons too. The cursor reacts to movements, but if you try to press something, everything freezes, except for the cursor. After some time, the action may be executed - but it may take a couple of minutes before that, even for a normal opening of the context menu.
I rebooted into a safe one - this is not there, I deleted what I installed (VirtualBox itself was not deleted, it required a service that was not running).
After the reboot back - the effect is almost the same, but at first the antivirus managed to boot, and then everything hung again. In between, I managed to launch the task manager and the performance monitor - it shows that the disk is 100% loaded, but sorting by processes did not show anything, since the real load was practically not visible. The monitor said that the most active system processes (System).
I killed all the processes that seemed leftist, but it didn’t get any better because of this.
Problems with hardware disappear, since Safe Mode worked, and now I am writing a question from under Ubuntu, everything is fine here too.
What could be the problem?

Answer 1

First, Andy or VirtualBox - you need to remove them COMPLETELY!
For example, using www.crystalidea.com/uninstall-tool or www.revouninstaller.com or www.iobit.com/advanceduninstaller.php
It is important to check if the related services and drivers have been uninstalled. And also view the "startup" records of Windows.
Personally, after such "Crashes", I prefer to reinstall the OS. Fortunately, today it is about 20 minutes with settings (but without updates) ... Unless, of course, you have 100500 programs with specific settings ...
Otherwise, after complete removal, try to do a "full MOT", for example using, for example, Advanced System Care ( www.iobit.com/advancedsystemcareper.or Auslogics BoostSpeed ​​( www.auslogics.com/en/)