Hi, In Avast free antivirus, there is a option of boot scan, in the scan now options. please log on to safe mode by pressing f8 and then open the avast user interface and schedule the bootscan and restart. Choose move to chest in the settings in the boot scan. Now you restart the computer,the avast will kill all trojans rootkits PUP at boot stage itself.
If you could not do so, try in safe normal boot and schedule boot scan. AVast is the vastly used free antivirus and it has also inbuilt a rootkit killer. In safe mode, it should work.If avast finds anything, again menu pop up for your choice of action, click move to chest and after reboot, go to chest and remove the rootkit or if you prefer choose delete in the options menu while boot scanning and it will delete, if found any more rootkits trojans etc
Thanks shane for recommending avast for me to my query on the other thread. I had been using mcafee with lot of intrusions before