First of all restart your computer and as soon as it will come back you will see a screen which says press F1/F2/Delete/ESC to enter setup or BIOS either of the key depending upon the motherboard of your pc immediately start tapping F8 function key and keep pressing it alternatively till you see a black screen like below
among all the options you need to select safe mode with networking
then login to the pc to the admin account or any account with admin rights
Now at the very first step download malwarebytes from the link below update it and run a
full system scan (sometimes the virus will not allow you to download it from there host so i
have also uploaded and provided alternate links make sure you always update it to the
latest virus definitions)
http://www.malwarebytes.org/after a full scan(time will depend upon the size of your hard disk and the data on it)
download superantispyware from the below given link and alternate servers and do a full
system scan(always follow the instructions after scan might be it will ask you to restart the
computer so do the needfull)
http://portable.superantispyware.com/sassaferun.phpnow download kaspersky virus removal tool from the below mentioned links and do a full
system scan and remove the malwares
http://devbuilds.kaspersky-labs.com/devbuilds/AVPTool/Now the final step which we should do for added security is to run a scan using Emsisoft
Anti-Malware from the given link
http://www.emsisoft.com/en/software/antimalware/Anyhow anywhere during the troubleshooting process if you find difficulty in downloading the softwares run the rkill software which will kill all the malware processes which could be blocking the software download
http://download.bleepingcomputer.com/grinler/rkill.com