Boot-file virus.
Boot-file viruses are able to infect both boot sectors and files, as they combines characteristic of both types of viruses. There's no need to describe the scheme of operating of boot-file viruses, as you understand their operating scheme is a combination of operating schemes of boot viruses and file infectors. If you are very interested on the scheme of their operating, please read the appropriate topic of the site.
The similarity of boot0file viruses with the boot and file infectors gives us a great opportunity to concentrate on concrete virus, exactly the notorious OneHalf, which infects main boot recorder and executable file. OneHalf virus is extremely dangerous one because of its ability to codify hard disk sector. Every launch of the operating system causes codifying of every next sector, as a time laps virus will codify a good half of hard disk and then reports you about the situation. It's not difficult to get understand why it is called OneHalf, because it sits steel until it damages one half of the hard disk. It's rather dangerous and harmful virus, moreover the results of its functioning are hard to dispose, just like the virus itself. Its main weapon is codifying.
OneHalf codifies system information of hard disk, and it's not enough to delete virus and infected files to heal your computer. To dispose the virus and results of its operating one have to decode coded information, sure it's a job for skilful professionals. No matter how frightened you are, no matter what pieces of advice you heard don't you even think to rewrite new uninfected main boot recorder. The best way out is to ask for professional help.
In case of emergency you may try to heal your computer yourself. But before you set to work, please make sure that there is no opportunity to reach a skilful programmer who would provides you with necessary high-professional help. You would better set to computer healing on your own only in case of urgent need in computer. Try to find appropriate antivirus program. You should know that all of the antivirus programs go out of date in rather short period of time, as viruses are constantly being improving by their creators, so you have to update the virus archive of your antivirus program. It's better to buy or download the latest version of antivirus program.
Remember that there are several types of antivirus programs; they are detectors, doctors, revisers, filters and immunizers. In case of penetration the boot-file OneHalf virus you should use antivirus doctors or revisers, as they performs functions that are necessary for detecting and disposing of OneHalf virus. Anyway, it's better to prevent problem than to deal with it, so I advice you to install antivirus filter program with permanent updating of virus information archive.