What should I do if Defender found a virus on my computer?

First off, you're right to be cautious. Reinstalling Windows via a USB stick can help, but make sure you back up your important files first. Change your passwords after the reinstall—especially for banking or sensitive accounts. I'd also recommend enabling two-factor authentication. And if you have any unknown devices linked to your accounts, be sure to remove those.

Here's a link to some official advice from Microsoft on handling that specific Trojan: [Trojan: Win32/Suweezy](https://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=Trojan:Win32/Suweezy#whattodo). It’s a good resource to see the recommended actions to take.

Check where the antivirus indicates the virus was found. Windows Defender usually highlights the location. If it’s in the system32 folder, that's definitely concerning. You might want to run a thorough scan with another antivirus program too!