What’s a virus?
“a software program capable of reproducing itself and usually capable of causing great harm to files or other programs on the same computer …”
– Princeton University
There are literally thousands or possibly millions of viruses on the internet today. It’s practically impossible to avoid them if you use a Windows PC or Server.
This guide discusses techniques for cleaning an infected system, preventing future infections and also discusses a less destructive but increasingly more common threat – spyware & malware.
How do I know if I have a virus??
Some common indications of an infected PC are:
- Quite sudden and unexplained performance problems i.e. Windows has slowed down suddenly. (Don’t confuse this with Windows slowing down over a long period of time.)
- Windows restarting your computer by itself
- Frequent crashes, hangs, lock ups, etc across multiple programs
- Trying to boot results in a blue screen
- Programs don’t launch when you double click the icon
- Files have 2 extensions
- Your antivirus program has being disabled and cannot be re-enabled properly
- You cannot access certain websites
- You are running out of disk space suddenly due to a virus multiplying itself
- Your anti-virus has notified you that a virus was found
Two possible scenarios –
1) You know the name of the virus or viruses you have been infected with or 2) you don’t know.
If you don’t know, find out. It’s essential that we know the name of the virus before cleaning it. You can find out by performing an online scan at one of the sites below.
All are free but will not repair the virus – they will only check and give you the name of the virus – which is what we need right now.
Now, you know the name of the virus
If you already know the name of the virus then you will need to either update your virus definitions and then run a full scan or if there is a removal tool available then you should download that and run it. Removal tools are available from the major anti-virus manufacturers such as Symantec and McAfee.
Symantec’s removal tools site is linked below:
Symantec: Removal Tools
If there is no removal tool available for the virus you have then it’s likely that running a full scan of your computer will clean the virus.
Removal tools are generally only required for particularly aggressive viruses that cannot be removed by normal scanning.
Running a full scan or using a removal tool
Now that you know what you have to do, here’s a few tips on how to do it successfully.
1. After you have downloaded a removal tool or updated your virus definitions unplug your PC from the network, internet, etc. The PC should be isolated from any connectivity.
2. Unplug any USB sticks or removal drives such as floppy disks, external hard disks, etc
3. Run the removal tool or full system scan in Windows normal mode first and then run it in Safe Mode if possible.
In Part 2 – how to remove stubborn malware & spyware including browser hijackers.