Signs Your Computer Has A Virus

Is your computer running very slowly? A common symptom of a virus is much slower than normal computer performance. However, there can be other reasons for slow performance, including a hard disk that needs defragmenting, a computer that needs more memory (RAM), or the existence of spyware or adware. For more information about spyware, see How to tell if your computer is infected with spyware.

Are you getting unexpected messages, or are programs starting automatically?
Some viruses can cause damage to Windows or some of your programs. The results of this damage might include messages appearing unexpectedly, programs starting or closing automatically, or Windows shutting down suddenly.

Is your modem or hard disk working overtime?
An e‑mail virus works by sending many copies of itself by e‑mail. One indicator of this is that the activity light on your broadband or external modem is constantly lit; another is the sound of your computer’s hard disk continually working. These are not always symptoms of a computer virus, but when combined with other problems, can indicate a virus infection.

Discovering Pop-up ads?
Running into a pop-up ad while you’re surfing used to be a serious annoyance, but modern browsers include pop-up protection to keep these annoyances away on most sties. If you’re still seeing regular pop-ups on more than one site, it could just be a badly-configured browser.
However, if pop-ups are coming at you when your browser isn’t even open, it’s likely you have a virus. This is especially true if the pop-ups advertise some magic cure-all to your “virus woes”. If you are bombarded with pop-up ads, first run a scan with anti-spyware software to double-check. I like SpyBot Search & Destroy because it digs deep into your settings to find any problems spyware has left behind.

Messages you didn’t send
Most viruses have one goal in mind once they infect your computer: to spread the virus as far as possible. An easy way to do that is to send messages to as many of your friends as possible in hopes they’ll get infected, too.
These messages can show up anywhere. The virus might try to send out spam through your email account. It could take control of your Facebook or Twitter and send out spam, too. In almost all cases, it will include a link or attachment to the virus somewhere in the post.
Keep an eye on your email’s “sent” folder and on your social network posts. If you notice emails and posts that you don’t remember sending or posting, it’s likely that you have a virus.

You’re locked out of your computer
You’re surfing the Web when suddenly a scary message appears saying you’re locked out of your computer. It may claim to be from law enforcement or an anonymous blackmailer.
Either way, the program is lying. What’s really happening is that a virus is blocking important programs from running, or even encrypting your files so you can’t get to them. The scam is trying to make you pony up some cash to get your computer back. That’s why it’s commonly called “ransomware.”

To check for viruses, scan your computer with an antivirus program. New viruses appear every day, so keeping your antivirus program updated is important.