Nephew's laptop still slow after SSD upgrade - found malware

[EldARon]

Hello

I'm helping my nephew upgrade his laptop with a new SSD. After the upgrade the laptop was still slow, especially after a bit. Then things begin to slow down. I discovered that Malwarebyte, Avast and Defender was disabled. I enabled all. Downloaded updates. I first ran Malwarebytes. It found the malware. See attachment. I then ran Avast and Defender, but they didnt find anything. I also ran a boot scan with both Avast and Windows Defender. The last I had to download a USB image, because it didn't want to run when I tried to start in from Defender settings. I'm still suspecting some malware/virus/trojan. And would appreciate your help again. 

//EldARon

Addition.txt

MWBfirstreport.txt

FRST.txt

[EldARon]

I just got notified that the Malewarebyte scan showed no malware. That was the report for the scan I took before I posted here. Here's the first report. Sorry.

I also know I should have made a clean install insted of transferring the system from the HDD to the SSD.

MWBfirstreport.txt

Edited December 31, 2017 by EldARon

[EldARon]

Reinstalled the computer.