Indication of virus' penetration.
Virus penetrates the operating system and infects software and hard disk sectors, virus activity just like any other activity can't remain unnoticed for a long time, the sequences of virus activity will show itself sooner or later. First of all it's important to say that virus' activity has to stages: active and passive. Active stage of virus activity is characterized by disappearing of files, hard disk's formatting and impossibility of files and operating system loading. If you have noticed such changes in operating of you computer you'd better activate your antivirus program in order to save your computer of further damaging.
The second stage of virus' activity is distinctive by:
- Disabling or errors in operating of software that used to work perfectly.
- Frequent fails and buzzing of computer.
- Computer's slow operating.
- Injection of abnormal audio signals.
- Impossibility of loading of operating system.
- Distinctive reduce of short-term memory volume.
- Erasing of catalogues and files or changes of their content.
- Distinctive increase of the number of files.
- Change of date and time of files' modification.
- Files' size change.
Therefore, appearance of the characteristics you've read above is not necessary the indication of virus' activity, all these factors may be caused by nonskilful operating of computer user, still it's better to test your operating system with antivirus program. Sometimes virus' activity results displaying of different pictures or sentences. It's an ordinary phenomenon that antivirus software sees no virus infection but anyway operating system of your computer operates with failures. In this case you may try to detect virus by means of files disassembling, it's rather difficult job but not impossible.
There are such kinds of viruses that are impossible for detecting basing on characteristics described above, such viruses are also remain invisible even after disassembling of infected file. Those viruses are able to codify their body and so hide it from disassembling and antivirus software testing. The viruses codify certain part of their body, those parts that operate at certain moment and after their work is done virus codifies them again. Viruses of this type are hard to dispose and the best way to save your computer from their damaging operating is to prevent their penetration into operating system by means of antivirus filter software.