I tried it on full scan and quick scans, both of them on default settings. I don’t know much about computers when it comes to this sort of thing, so I leave settings on default, assuming it knows best.

I suppose I can also mention that I installed malewarebytes to check, and it hasn’t found anything.

I too find it hard to believe I somehow got over 1000 rootkits, but just having avast tell me that is enough to scare me beyond words.