Farbar Recovery Scan Tool, or FRST, is a free portable application designed to diagnose malware issues. Available for 64-Bit.

For scanning and live protection, consider downloading Malwarebytes.

It is also possible to run FRST in the Windows Recovery Environment to diagnose and fix boot issues.

Farbar Recovery Scan Tool quickly scans and then displays detailed information about the Windows Registry loading points, services, driver services, Netsvcs entries, known DLLs, drives, and partition specifications. It will also list some important system files that could be patched by malware. The report provided is automatically saved as FRST.txt in the same directory as the original download for easy access. It contains a lot of information but is presented in a relatively easy-to-read format.

Consider using Malwarebytes for complete antivirus protection and to protect your devices, data, and privacy.

Similar:

What's the Best Antivirus and Is Windows Defender Good Enough?

What to Do When Your Norton or McAfee Antivirus Expire

Limitations:
If you are using Windows XP and have a boot issue, the system should boot to the Recovery Environment using a PE Boot CD and then you can run FRST