Infected.

I am infected with a trojan, I injected a dll. It turned out to be some kind of RAT/Trojan.
It disabled my windows defender, how do I renable that?

Depends on how complex the virus is, one option is to format the drive that is infected, another is to download malware bytes. If nothing else, reformat your entire PC.

Go into settings - security - windows defender - set to on position. This is for windows 10. Other windows os will be similar. Hope this helps.

I'm not the most advanced with this type of stuff, but there is a program used to get rid of the most popular RAT Dark Comet. Just search up Dark Comet RAT remover into google and it should pop up.

format your drive

I usually use Hijackthis with the Hijackthis Log Scan. You can easily use it and find any virus processes. Also, use a good antivirus to remove it.

Once I get infected I usually prefer to format (safer)

Try downloading malwarebytes chameleon or something like that, jrt, or adwcleaner. Make sure to reboot into safe mode before.

Simple & Secure way › Format

Easy & Fastest way › Scan with HiJackThis and post your scan here & check which process is your virus and remove it. You should run AV and Malwarebytes tho.

Just do a system restore or locate file

I got the problem solved that month, thanks for all the support guys!