Computer viruses and malware can cripple a machine at their very worst. But even if your PC hasn’t gone into total meltdown, it’s perfectly possible that a virus is on your system and causing less dramatic disruptions.

The question is, how can you tell if your PC has been infected with a virus or malware?

How to spot a computer virus

First things first, forget everything you’ve ever seen in a Hollywood movie when it comes to computer viruses. Hollywood scriptwriters can write many things, but a convincing approximation of a virus code isn’t one of them.

Viruses do not make a giant skull-and-crossbones appear on your screen. It would be very unlikely for a virus to make your screen suddenly warp and flicker. And they tend not to make your speakers turn on and laugh at you.

The actual signs to look out for are more mundane, but can be just as frustrating.

A slow-running computer

Top of the list of things to look out for is a PC that’s running more slowly than usual. If you’re finding that your system is grinding to a halt, it’s possible that a virus has infected your PC.

Make sure your anti-virus software is up to date and run a full-scan immediately.

Frequent program or system crashes

If you’re finding that your computer is regularly crashing, or that programs are freezing frequently, a virus could be to blame.

Try using the Windows Reliability Monitor to see a history of your computer’s performance. This ought to give you a better impression of how often it’s been misbehaving, and if there’s been a significant increase in crashes recently. This could tip you off on a virus infecting your system at a certain point.

Problems accessing files and folders

If you’re struggling to open files which normally present no problems, or if your folder structures seem to have changed, it may mean that a virus has infected your computer.

As a virus spreads and corrupts files on your system, it’s not unusual to find that these files are difficult to access. Sometimes even opening a folder can cause your system to hang or crash.

The best defence is a reliable suite of security software. Kept up-to-date, security software can typically fend off the worst threats from the web.

Have you ever experienced a computer virus on your system? What were the symptoms you noticed, and how did you deal with the problem? Share your experiences in the comments below.