Firefox keeps installing, Chrome & other programs shutdown

[HyDrApt]

So my PC is running weird for the past few days.
I've seen firefox installed (without me or anyone else installing it) and not showing up on programs and features.
Other thing is, while it's installed, my chrome keeps shutting down, on it's own, along with other programs (discord and battle.net)
This is a malware, for sure, and i've ran Anti-Malware bites. It has found 4k threats (after running for the second time, while on the first time it found 1k). I've quarantined the threats. I've also downloaded the anti-rootkit program for kaspersky and it has found 2 threats.

Any tips, or should I just format my windows? (been wanting to do this for quite awhile)

 

[t53186]

Perfect time for a clean install.

 

[schwatzz]

4 000 detected threats? If you did any banking or used your email on that computer, now would be the time to change all of your passwords too. Just be careful too, even after a clean install, there maybe a chance some of the malware lingers.

 

[HyDrApt]

The 4k threats appeared today, after I ran anti malware yesterday (which found 1k).. something is really off

 

[schwatzz]

When you run your anti-virus, make sure you are disconnected from the internet, just in the case the malware tries to "phone home". If you share files with other computers over your network, run Malwarebytes on all of your PCs. Make sure "root kit detection" is on and run a full scan. But, as t53186 suggested, a clean install would be your best bet. Make sure you have an anti-virus installed like Avira or Avast.