This computer had an interesting problem:

You could visit most websites, except for google and youtube.

When you go to google.com, you get a 404 error, and then, underneath, in small writing: nginx

Also: system restore would not work.

A scan with malwarebytes removed a few infections, but the google problem persisted.

A search uncovered a few possible solutions:

• Make sure the hosts file at: C:windowssystem32driversetc only has one entry (127.0.0.1 localhost)
• go to: internet settings -> connections -> lan settings -> make sure no proxy settings are ticked
• make sure the internet dns settings are obtained automatically
• use tdsskiller to remove hidden rootkits

In my case, malwarebytes fixed everything… but I still needed to use tdsskiller to fix the problem with google (which was caused by a rootkit).

I wonder if malwarebytes is capable of detecting and removing rootkits?