How do I download antivirus or cleanup on to flash drive?

Need to know in plain english how to load antivirus or cleanup on to flash drive to get my computer back on track.  Already go instructions and websites to go on and which antivirus cleaners to use but not sure how to load them on a flash drive or how to proceed once they are on it and I plug it in to my computer.  Thanks.

Download program (using computer that's not infected) and save it to a flash drive that's inserted into USB Port.  Insert flash drive into infected computer and run program from flash drive.  Or if using Malwarebytes Free and similar programs you'll need to download the installation file, save it to the flash drive anmd then run the installation file on the infected computer - be sure you change the name of the installation file to something like 1234.exe.

Another alternative to combat malware is using an offline scanner:  http://ask-leo.com/windows\_defender\_offline\_scan\_your\_computer\_for\_malware\_without\_booting\_windows.html?awt\_l=Bg3x\_&awt\_m=JqgKoVn.FZdfbL

Good luck...