A secret virus or the damage it made?

[Jakers038]

A month or so ago I downloaded some gray-ish programs and I got a trojan warning, in the file description from where I got it, it said it was a false warning and I was dumb and just ignored it, since I didn't get any viruses in years and stopped caring about them.

 

Everything was still fine for a few days and then one day the computer slowed down to like 1/10 of it's speed, it took ages to boot up (the part when you already get to the desktop, but wait for everything to load up before any programs can open, this was like 10+ minutes), I used Avast, Malwarebytes and Kaspersky to fully check the computer, but no viruses have been found at all (and the actual process of finding the virus was extremely slow), but I still knew what program was the likely source, so I deleted all files of that program and even though the files were on D partition and not C where my OS is located, that kiiinda did the trick. Since I deleted the files, the computer is much more responsive, but it still loads up much slower than it used to before all this. I don't have any programs that startup with windows and task manager doesn't show any strange apps or any high resourse usage. I tried the windows defender antivirus thing as well, but again, nothing.

 

If I open up some games that ran without issues before like Just Cause 3 or RDR2, in the first one it runs slower than it used to and sometimes I get choppy frames, which I never had before, and with RDR2, it always first loads up in a black screen, so I have to press alt+enter or open the task manager and return to the game and only then does it show up normally. Afterwards it runs with a good FPS. I tried even defragging, but nope, not the issue.

 

So TLDR, I got a virus that completely slowed down my computer, antivirus programs did nothing, I deleted the files which carried virus and that sped up the computer, but it's still slower than it used to be a month ago.

[Jurrunio]

Maybe it has setup some background tasks already?

 

Fastest way to check tho is a new OS install, could do so if you have an empty SSD or HDD around

[Praesi]

Reinstall Windows and check all other Drives for seeds.

 

And dont trust a shady webside saying its a false warning..lol.

[PorkishPig]

Try running Autoruns from https://docs.microsoft.com/en-us/sysinternals/downloads/autoruns. Look through it and see if you can spot and software you don't immediately recognize. If you're not sure about a particular program, send over a screenshot.

[jjbeebe]

Using a boot time scan or rkill may help in the removal. This may be an option to try before reinstalling window, boot time scanners are better at killing entrenched malware. 

 

Rkill 

 

https://www.bleepingcomputer.com/download/rkill/

 

boot cd/usb options 

windows defender

 

https://support.microsoft.com/en-us/help/17466/windows-defender-offline-help-protect-my-pc

 

comodo

https://www.comodo.com/business-security/network-protection/rescue-disk.php

 

sophos 

 

https://community.sophos.com/kb/en-us/52011

 

After performing a scan use DISM to fix corruption in windows 

 

Open Start.

Search for Command Prompt, right-click the top result, and select the Run as administrator option.

Type the following command to repair the Windows 10 image and press Enter:

DISM /Online /Cleanup-Image /RestoreHealth