Trick to make system clean again after virus attack.
1Using Backup Software -:
Backup the OS partition with Clonezilla(Download it), this is a free app. Every time your OS has any problem just use Clonezilla to replace the OS partition, it will take max 10
minutes

2.From Linux( Ubuntu)-:
Now if you are using Linux on your computer then you are more familiar with the maximum security advantages of Linux (Open Source Software) than its rival Windows and Mac, because the most of the virus and malware are made for Windows and Mac. Also most of the computer has no knowledge about how to remove virus/malware from Windows using Linux.
Malware and Viruses are devastating for computer as well as for users too. It is difficult or even impossible for using computer and it is also dangerous to use it. So Linux comes up for rescue your windows.
This is simple trick .Sometimes it may not work for latest viruses or malware..
1. First of all download Linux .iso file from this link.
2. After download burn it in disc or pen drive to make LiveCD. LiveCD means you can boot your computer without installing operating system like you do with Windows.
3. Once you make LiveCD or pen drive turn off your computer and boot again from LiveCD or Pen drive to boot the computer into Linux to bypass the Windows and its infection.
4. After complete loading Linux it is time to wipe out viruses and malware. I recommend to use Linux based antivirus named “ClamAV” from clamTK
5. Go to Applications from Ubuntu (One type Of Linux) Desktop. Then go to “Ubuntu Software Center”. Choose “Edit” and then “Software Sources”. A box will come up with title “Download from the Internet”. Be sure to check all four boxes before you click on “Close”.
6. Now from the main Ubuntu Software Center page, click on the “Accessories” icon and type
ClamTK into the search box. It will show as “Virus Scanner”, but if you click on “More Info” you can verify it’s the right package. Click “Install” and wait for it to download.
7. Once your installation is complete, you should ClamTK by going to “Applications” in main menu of Ubuntu. Then click on “Accessories” and “Virus Scanner”, which is how the software will still be shown.
8. RUN A SCAN-: When the ClamTK opens, click on the”Scan” tab and select the option for Recursive Scan. Next you can choose which drive you want to check for viruses and malware. Once the infection is found you get the options for what to do with it, including quarantine or removal.