How to remove malware from a computer I loaned to a friend

This article was modified on 2012-01-02 19:15:44

If you recently borrowed your computer or laptop to a friend, colleague or anyone else, there is a high chance for being compromised. I am talking about viruses, spyware, trojans, worms or any other type of malware.

There are two probabilities :

1. You borrowed your computer to a friend that doesn`t know what he was doing and he infected your computer without his knowledge.

2. A friend with a real talent when it comes to technology such as computers and Internet will install some sort of malware in order to spy your activity such as a keylogger ( a software designed for spying capabilities – running invisibly which is able to record keystrokes, passwords, e-mails, activate microphone, activate webcam etc. )

If it`s the second probability, in most countries, it`s illegal and I don`t know if it`s a good idea to go to police if there are no financial or privacy issues.  If you experienced any kind of losses, I would recommend you to consult your attorney.

Regardless of these scenarios, here`s what you could lose :

- someone else would also know and have access to all accounts such as your email and all other websites out there.
- if you use online banking, Paypal account or pay with your credit card, I guess you`re not the only one and someone else can access them anytime.
- depending on what kind of malware was installed, everything on your computer is being recorded and sent to a third party

What should I do ?

If you`re going to change your password, cancel your credit card and so on, it`s not enough. Each time when you will use your computer you`re going to do the same thing, the malware will re-send everything so you can`t win.

Sure, you could scan your computer for malware using an antivirus ( there are plenty of them ), an anti-spyware software such as SpyBot Search and Destroy but if you`re not knowledgeable enough you`re not going to solve this issue. Also you can`t rely on a software, there is no such thing as a 100 % and guaranteed security solution. Also, if we’re talking about keyloggers, most of them were created with one purpose in mind: for being completely invisible so most of the anti-spyware products won’t even detect them.

The answer

The safest approach would be to backup, completely reformat your computer and perform a new, fresh reinstall.
When a machine has been compromised, the best thing to do is to erase everything and start over. Don`t forget about a backup of most important things

Tip: A couple of years ago, my computer got infected. I didn`t borrowed my PC, it just happened. I had several e-books, pictures and other info that I couldn`t afford to lose. What I did was to write them on several DVD`s and now when I am accessing them, the antivirus blocks the virus but my info isn`t lost, it`s there and this was the only method that I could find at that time and date.

Conclusion: If you`re reading this article because you borrowed your laptop/computer to someone else, please try to remember that each device that`s not physically secure, it can be compromised. If a determined person, a friend, a colleague has the knowledge and he knows what he`s doing it will be able to access all your data, compromise any account that you own and install malware such as a keylogger with remote-feature functions. It means that it can even activate your microphone, activate your webcam and so on. It`s creepy but search on the Internet and see how many complaints you will find. Definitely, take a good look at your friends and if someone did this, try to get a better friend.

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