I don't know I am no expert in the field, I am still learning.

But I dont think any kind of "detection" tool can be trusted. If the virus is already in, then it can just simply hide itself from the detection tool, and feed fake data to the detection tool.

All viruses have to be treated as smart ones, so evading any kind of detection has to be assumed.

The OS has to be reinstalled from a trusted DVD, there is no other way.