How virus enter the computers?

Answer 1

They look for insecure operating systems like Windows and attack them.

Answer 2

The "enter" through bad programming practices, poorly written computer code, and "Operating Systems" that are actually micro-managment systems and NOT Operating Systems at all.

The biggest offender is Microsoft Windows. The best way to shield against this is to use a Linux based product, such as the MAC OS or Linspire or SuSe Linux.

Answer 3

Some Ways That Viruses Can Be Transmitted And Spread

E-Mail Attachments: Email attachments are the most common way that ill intentioned people transmit viruses in order to infect computer users. Therefore, you should always apply caution when opening any E-Mail attachments received, especially from people who you do not know. These types of viruses are usually triggered when the attached file is opened or executed. Some viruses can even trigger themselves just by simply viewing the infected E-Mail although this is not that common. Therefore, ensure that the Anti-Virus Software you are using is set to monitor your E-Mail Program that you send and receive E-Mail with. Today’s modern software programs are usually set by default to do this.

Network Shared Resources: Many viruses and worms will try to duplicate themselves by finding security loop holes in a network in order to attach themselves to a shared network resource. The most vulnerable network resource are file folders, which are shared amongst users as file access permissions are being granted. When a Virus identifies a shared folder it will attempt to copy itself into it in order to infect that Computer itself and then all computers that access the shared folder. A Worm will basically just try to replicate itself. However, it is possible to limit this risk by setting access permissions for the shared folder. If your network is set up with any shared folders, then you should have your network administrator take the appropriate action to secure them.

Removable Media: Removable Media such as Floppy Disks, Re-Writable Compact and DVD Disks, Zip Disks, USB Memory and Flash Drive are often exchanged and used from one machine to another, especially in an office. Therefore, be sure to frequently scan these removable devices to prevent infection. Today’s modern Anti-Virus software will contain a built in feature where you can simply right-click on the Removal Device itself within My Computer or Windows Explorer and then choose a menu option to scan that device. In other words, if you want to scan a floppy disk, then right-click on the A: Drive within Windows Explorer and then choose a selection on the order of Scan for Viruses.

Internet Downloads: Any material downloaded from the Internet, whether they are programs, documents, music files, video files and compressed files etc., could potentially contain a virus. Therefore, be sure to scan these files first with your Anti-Virus software before you launch them. Today’s modern Anti-Virus software will usually be set to scan these downloaded files for you or at least prompt you with a reminder to do so. If not then do it manually.

Answer 4

in a program cracked or disegned to damage your system this virus damage your system in different places of your system like registry data or autostart program, or hide installation .
be carefull in internet the pages with most virus are the serial and another things free
espero me entienmdas no se mucho ingles

Answer 5

Someone got on the internet and clicked on something, or opened an attachment on an e-mail, or downloaded something stupid.

Answer 6

Read this information:
http://askcomputerexpert.ws43.com/security/

Answer 7

from a download...... dont do it unless its from a secure website or from someone you know and trust.