Modern malware is designed to stay hidden for as long as possible. Even so, it almost always leaves signs that something's wrong. Here are the most common ones.
1. The computer is much slower than usual
If your computer suddenly slowed down without you installing anything new, malware could be running in the background eating up CPU and memory. Check Task Manager (Ctrl+Shift+Esc) and look for oddly-named processes using a lot of resources.
2. Pop-ups and adverts everywhere
Adware shows intrusive advertising: pop-ups, adverts on sites that don't normally have them, or redirects to pages you never asked for.
3. Your browser has changed on its own
If your homepage is different, your default search engine has switched to one you don't recognise, or toolbars you never installed have appeared, you have a browser hijacker.
4. Your antivirus has switched itself off
Some advanced malware disables antivirus software to avoid detection. If Windows Defender shows as switched off and you can't turn it back on, that's a serious sign of infection.
5. Programs opening or closing on their own
If programs open without you doing anything, or your mouse cursor moves by itself, it could be a remote access trojan (RAT). This type of malware gives an attacker full control of your computer.
6. Encrypted files that won't open
If you find files with strange extensions that won't open, along with a message demanding a ransom, you've suffered a ransomware attack. Turn the computer off immediately and call a technician.
7. The hard drive is constantly working
If the drive light keeps flashing even when you're not doing anything, something is running in the background — possibly a cryptominer using your computer to mine cryptocurrency.
8. Odd charges or activity on your accounts
If you get notifications of logins from unfamiliar locations, or find charges you don't recognise, a banking trojan may have captured your passwords.
What to do if you think you have a virus
Stop using the computer for online banking or entering important passwords. Bring it to us — we do a full virus and malware clean-up without losing your personal data.