There are several signs that your computer may be infected with a virus. Some common symptoms include:

• Slow computer performance
• Unexpected pop-up windows
• Unwanted programs starting automatically
• Missing or corrupted files
• Frequent system crashes or blue screen of death
• New applications or processes appearing on the background
• Overworked hard drive
• Spam emails sent automatically from your account without your permission
• Browser redirects
• Disk is full due to virus leaving a copy of themselves and creating duplicates of system files that fill up your disk space
• Inability to download antivirus program updates or a malfunctioning firewall

If you are experiencing any of these symptoms, it is worth checking if your computer has a virus.