ComboFix is usually a malware utility "of last resort", that shouldn't be used unless you're fully aware of what it does. Normally, we carry other malware utilities like MalwareBytes and TDSS (Root) Killer on our USB sticks carried for work (IT). On my personal USB drive, I have many of the PortableApps programs like LibreOffice, FireFox, Thunderbird, etc. For those who have any sensitive data on the drive, TrueCrypt is a must.