you should take action immediately to clean the infected files from your hard disk. The more you delay this, the greater the chance that more files will get infected.
And if system files (the ones associated with your operating system) get infected, then formatting your hard disk may be the only option. However, those are last resorts only. For now, let’s see whether the infection can be cleaned up without taking any drastic step.
Backup Files Before you do Anything
Do not neglect this, or you may feel sorry for that later on. Remember, if the infection is severe, then you may end up formatting your hard disk anyway. In that case, a backup will keep essential files from being lost forever.
Always back up the files on a removable hard disk, or external memory drive of some kind. Do not take the backup on another partition of the same hard disk as the one containing the infected files.
Research should be carried out as a prevention on how to prevent malware from infecting backed up data during the back-up process.
Scan the Entire PC
Download a good quality antivirus and antispyware tool and scan your entire PC with those. Remember to update both tools before you run these. You will probably find a number of files that have been infected. Note down the names of any system files that show up as infected ones in the scan report.
Reboot in Safe Mode and Remove Files
Restart your PC in safe mode and run the antivirus and antispyware tools once more. This time, quarantine the infected system files (if any) and simply delete the data files that show up as infected in the reports.
Remember, if you are not sure whether a particular file is required for Windows operating system to function properly, quarantine it instead of deleting. That way, the malware infecting the file will not be able to become active anyway. Later on, you can look up the name of the file on a search engine and decide whether you should delete it.
However, remember that if you find that a large number of system files have been infected with the malware then you may be better off reinstalling the whole operating system. Otherwise, the infection is likely to infect your entire hard disk over time.
The operating system could start behaving abnormally, and any new files you create or download would likely get infected as well. Do the reinstall by yourself, or if you are not feeling confident enough, then call up a system administrator to get it done for you.
Credit : Mar 22, 2011 Anne Envisonite
Source : How to Delete Infected Computer Files
