HitmanPro is the fastest solution to see if your computer is infected with viruses. This software is also portable and can run from a USB Flash Drive, CD/DVD, local or network attached hard drive. Hitman Pro 3 is a fast all-in-one tool to locate, identify and remove viruses, spyware, trojans, rootkits and other malware. Hitman Pro 3 will quickly show if your PC is infected with malicious software.
McAfee Stinger is a standalone utility used to detect and remove specific viruses. It is not a substitute for full anti-virus protection, but a specialized tool to assist administrators and users when dealing with infected system. It's a freeware post
Recently there are many case reported that "autorun" virus spread through so many computer due to using flash memory or pendrive, so we need a preventive action to stop this virus spread to our computer! USB drives are so popular and generally get used to move data between multiple systems frequently. Even though USB drives are very useful, they are potential breeding ground for viruses. When you stick your flash drive the host computer will look for commands in "autorun.inf" to be executed automatically. Normally those commands in "autorun.inf" are harmless, but if the file was modified, it may call for execution of a Trojan or whatever program in your USB flash drive automatically. Naevius USB Antivirus is a tool which protects your pen drive from autorun-viruses.