Windows Defender Offline is free antivirus software from Microsoft. With it, you can boot up any computer and get rid of resident malware, even when Windows is out of action.
To install it, you just need a CD, DVD or USB flash drive with 250 megabytes of free space. If you want to burn Windows Defender Offline later, you can also create an ISO file.
When you boot up the PC with the CD, DVD, or flash drive, Windows Defender Offline starts a limited version of Windows, with which it is only possible to run an antivirus scan.
Choose the disk to scan and wait a few minutes until Windows Defender Offline finishes removing viruses. To update it, just run the Windows Defender Offline installer again.