Instructions

1

Take note of the speed of your computer. After contracting a virus, you may notice that your computer runs at a slower speed. Programs often take much longer than normal to load.
2

Read any error messages you receive. When you have a virus, you'll likely see some sort of error message appear. Error messages usually pop up when you're shutting down or restarting the computer.
3

Check your computer's files. If you suspect a virus, you can look at your computer's history and see if any files or folders have recently been modified or added without your knowledge. Look at the folder's name and type it into a search engine to see if any info about the virus appears.
4

Run a scan using anti-virus software. After looking for the signs of a virus, you can detect the virus with your anti-virus program. Run a complete scan of all files and then remove or quarantine any viruses found by the program. Norton, McAfee and AVG all provide anti-virus software.