There are some portable programs that could be used without installation. In same way there are some portable antivirus programs too. You can store them in your USB drive and carry wherever you want.
McAfee Stinger portable:
As you know McAfee is among best antivirus companies due to its protection against viruses. Now this company is giving a free portable antivirus that you can carry with you. You can use this to scan your friend’s computer to destroy viruses. You can use this to protect your pen drives because lots of people haven’t installed antivirus programs. You can scan such computers using this portable antivirus.
This is also best freeware antivirus and you can also get its portable copy from cnet.com. Visit here (Portable version download from cnet) to get its portable version. You can use it without making any installations. This antivirus provides you standard features as other antivirus programs but this is portable too.
If you want to know more about this antivirus then visit its official website www.safer-networking.org
You can get free portable version from cnet.com not from official website.
You should install antivirus to get maximum security. There are some Freeware antivirus programs too that you can install to get maximum security. (Also Read: Best free Antivirus)