Rovnix is a nasty trojan virus. Google it and you’ll see. There are many variations on the Rovnix theme, but they come down to this symbiotic combo: DOS versions, which hide in the boot sectors of your hard disk, and WIN (Windows) versions spawned by their DOS cousins every time you restart your PC.
It’s fairly easy to remove the WIN versions, which infect other files, steal passwords and turn other tricks, but the DOS versions, like antibiotic-resistant bacteria, are difficult to kill off.
Competent anti-virus programs, such as Microsoft Security Essentials, and anti-malware programs, such as Malwarebytes, will detect Rovnix infestations, i.e. Win32/Rovnix.gen! C and DOS/Rovinix.W. They may even offer to remove the viruses, but only succeed in removing the Windows versions, which reappear after the PC is restarted.
It is possible to remove Rovnix manually, if you are familiar with file commands and working with the Windows registry. There are also tools which can be run from a USB drive or CD booted up before Windows starts. But these methods are not for most PC users and can create problems if misused.
Kaspersky Labs, the highly respected security company, offers a free utility which runs from within Windows — any version — and removes both variants of the Rovnix trojan virus with no hocus-pocus and no brain strain. You gotta love the name: TDSSKiller. It’s a powerful utility which removes not just Rovnix variants but a wide variety of rootkits, bootkits and other malicious software. You can get TDSSKiller here.
P.S. A side benefit of TDSSKiller is its specificity. If you run it on a clean system, it will do no harm.