Copy EnglishFRST64.exe to a flash drive and access the Command Prompt like you did before.
Connect the flash drive, start Notepad and see if you can identify the drive letter corresponding to the flash drive (take note of it) and close the notepad.
In the command window type e:\EnglishFRST64.exe and press Enter
Note: Replace letter e with the drive letter of your flash drive.
Run a Scan and post the generated FRST.txt log.