Hi @nyazilla ,
Do you have access to another PC that has a 3rd party AV (anti virus) program installed?
Most AV programs have what they call a Rescue disc option, which allows you to create an AV boot up disc and run the AV program to scan the HDD for viruses and rootkits without having to start Windows.
Here's an example only which explains it better than I can.
As I said most AV programs have a similar option. The one above is as I said, an example only of what is available to try.
It saves having to lose all your data by doing a clean install, if you haven't got a recent backup.
Alternatively can you do a system restore back to a point in time before you installed the rootkit?
Go to Control panel > recovery