A knowledge base article about Cleaning an Infected Computer of Malware provided by the UC Berkeley IT Service Hub - Knowledge Portal
Attackers often leave “backdoors” on a compromised computer, and removing them all can be difficult, if not impossible. We recommend reinstalling your operating system, but if that is not practical, you can try this option first.
Note: If you receive a security notice from ISO after attempting to clean the computer, you MUST reinstall the operating system (see Reinstalling Your Compromised Computer for instructions).
Windows machines come with Windows Defender, but you must turn it on. See instructions for various Windows systems.
See the instructions for booting into Safe Mode.
2.1 Once in Safe Mode, you’ll want to run a virus scan. But before you do that, delete your temporary files. This may speed up the virus scan, free up disk space, and even remove some malware. To use the Disk Cleanup utility included with Windows, just type Disk Cleanup in the search bar or after pressing the Start button and select the tool that appears named Disk Cleanup
2.2 Next, while still in Safe Mode, run a full scan of your system: Double-click on the white Windows Defender shield icon in the icon tray bar (notification area) on the lower right portion of your screen and select. When you hover over the icon, it should say "PC Status: Protected."
2.3 On the "Home" tab, select "Full" and click the "Scan now" button.
3.1 These programs have free versions that can be run for personal use and have solid reputations.
Note: Some adware/spyware alerts, particularly cookies, may be fairly innocent and not represent a serious threat to your system's safety. The alerts you should be concerned about are primarily those that show installed programs or browser plug-ins/add-ons you cannot identify.
If these steps do not return any significant problems, then the system is probably ok to use. However, watch for any issues you notice. If these steps do not resolve the issue, you must rebuild your operating system: Reinstalling Your Compromised Computer.
* This list does not represent endorsement by the University of California or its affiliates.