How to protect and disinfect your computer....

HOW YOU CAN GET INFECTED

Booting the computer from an infected hard disk, cd-rom or diskette.

Executing attached infected files (.exe, .com, .vbs, .dll, .sh, .bat , .scr, .pif and more) you may find inside emails.

Executing infected files (.exe, .com, .doc, .bat, .hlp, .htm, .ini, .js, .php, .pif, .reg, .ppt, .scr, .sh, .shs, .sys, .vbs, .wbt, .xls and more)

Previewing emails usually sent by an unknown person, because they possibly contain destructive code in the form of .html, that is automatically executed upon the email preview.

Browsing infected webpages (usually .htm and .html ).

Just by using the internet. To be more specific, almost every operating system, especially Microsoft Windows, have "security holes" which are exploited by a new type of viruses in order to infect the computer, without asking at ANY point the permission of the user to install any type of software.

HOW TO PROTECT YOURSELF

Make a backup of your critical files regularly, after having scanned them with an antivirus program.

Update your antivirus program as often as possible.

Scan every file you download from the Internet.

If you use irc chat, make sure you have disabled the auto-accept-dcc-files option.

Try to have a real-time antivirus monitor while your computer is operating.

Don't visit every website you are invited to by an unknown person. It may contain a non-visible destructive applet.

Disable the execution of java or active-x scripts within your browser.

Unhide the hide-file-extension-of-known-filetypes option within your hard disk explorer. If someone sends you a file called pic.jpg.vbs, you may think it's a .jpg file and execute it!

Always have a boot disk for repairing your computer in case you get infected. Most antivirus programs offer this disk.

Try to use two different antivirus programs, using only one real-time monitor.

Use a firewall program (we recommend Sygate Personal Firewall or Outpost Firewall Free or Comodo Personal Firewall or Kerio Personal Firewall, which are absolutely FREE and manage to protect efficiently any personal computer ).

Use an anti-spyware program .

Try to update the operating system of your computer often (especially Microsoft Windows), so that all known security holes are fixed. We should mention that certain Microsoft operating systems do NOT allow the user to install updates if they have not been purchased!

WHAT YOU SHOULD DO IF YOU GET INFECTED

Avoid installing an antivirus program if you are sure you have been infected by a computer virus.

If your antivirus program detects the virus but cannot repair it, do NOT delete the file! Try using another antivirus program, maybe it will be able to repair the infected file. None of the antivirus programs is perfect, still, the difference among them may be huge!

Do NOT format your hard disk! Formatting is NEVER a 100% guaranteed solution in order to face a computer virus. Have patience, faith in the antivirus program you have chosen and ... a bit of good luck!

What are computer viruses......

The continuing growth of the number of pc users over the last 25 years triggered a small group of people to get down with something that today many find foolish and dangerous : they decided to develop programs that would make the computer "go crazy" or even mulfunction for a certain period of time, either for the laugh of it, or, maybe, just to harm the computer of someone they really dislike! Still, if you find out today that your computer has a virus, you will probably panic .. And you will be right, cause most of the 75-80,000 viruses these days are certainly NOT something to laugh with!

What is a computer virus

A sequence (or a series of them) of symbols, that when executed under certain circumstances or a certain operating system, they create an exact replicate of the sequence, which they install into the hard disk or diskette. The installation usually takes place inside a directory commonly used. Of course, a virus may also have a payload function, by which it will damage the infected computer.

TYPES OF MALWARE

Trojan horses / Backdoor programs

They are surely the most famous type of viruses. They include a code, upon the execution of which, the host computer becomes valnerable to a malicious remote user. Hacker-wannabies and "lamers" usually use these viruses to "hack" :P other users. But that's not all … Some trojans and backdoors may even delete important files of the hard disk, or even format it. Fortunately, they cannot reproduce and for this reason many do not even consider them as "real" viruses.

Polymorphic

We call polymorphic a virus that hides its destructive code within the infected file in several different ways. The particular type of viruses is more difficult for the antivirus programs to detect, since there barely is a same routine inside each virus sample.

Stealth viruses

They use the memory interrupts of the computer. Once a program calls a memory interrupt, the virus gets activated instead of the program itself. Stealth viruses perform one more function. They are capable of hiding from antivirus programs. That means, whenever they detect a scan function by the antivirus program, they temporarily restore the original non-infected file, so that the antivirus program will believe that there is are no viruses inside the system. Once the antivirus has finished its scan, they infect the file again. The specific method of hiding is often called "tunneling”

Parasitic a.k.a. Appending viruses

They are called parasitic cause they infect the original file, copying the destructive code within it, without making the original file irrepairable. Once the user executes the infected file, the virus is activated without letting the original function of the file to be executed.

Overwriting viruses

The simplest way for a virus to infect a computer is to merge itself with a well-known file. This way the original file CANNOT be restored. Some of these viruses have the ability not to alter the original filesize, so that some antivirus programs will not see the difference in the original file. Nevertheless, most coders do not make such type of viruses anymore.

Companion viruses

They are viruses that are executed usually under MS-DOS. When the user types a DOS command (e.g. "edit") and the file edit.exe is not present, the OS will execute the file edit.com, which really is the virus itself. Still, if the user types "edit", the OS will execute the virus (edit.com) and not edit.exe, which is the real editing program!

Retro viruses

They are viruses that do nothing but "fight" a specific antivirus program, meaning that if they detect it inside the hard disk, they will delete all components of it.

Logic bombs

They are viruses that activate upon a certain trigger date, e.g. at 14.00 of 13 of September. They usually have a destructive payload, such as deleting files.

Droppers

They are executable files that contain the proper commands to create a virus inside the pc but do not include a virus themselves. They are harder to detect than a normal virus.

Worms

They are called worms because they are usually found in computer networks. They use the Internet as a medium to spread (emails, irc chat etc).

Boot sector viruses

These viruses infect the boot area of the hard disk or diskette. They are the ones to blame for most infection worldwide. You do not have to have an MS-DOS based OS in your pc to activate such a virus, since they do not make such .. discriminations. E.g. although the Michelangelo virus cannot spread using Windows NT, he still can wipe out the contents of the hard disk on March 6th!

Direct action viruses

These viruses just execute their destructive payload and are not memory resident.

Macro viruses

They are the well-known viruses that infect using a macro-command. They harm only Word, Excel, Office, PowerPoint and Access files. They are very easy to spread. Most typical example you can find is Microsoft itself, who - is believed to - had a macro-virus inside the first edition of MS Office ‘97.

Multi Platform viruses

They are viruses that affect on more that one operational systems. Usually, a virus that affects Windows OS, cannot harm an Apple pc.

source : www.virus.gr

Dr Solomon's Anti-Virus 7

Anti-virus programs are a boring but vital part of safe computing. If you value your data and your time, you definitely need a reliable means of routing viruses before they can do any damage. There are quite a few anti-virus programs on the market now, with Dr Solomon's Anti-Virus being very well regarded.

How it work ?

Dr Solomon's Anti-Virus attacks the virus problem from several fronts:

• Before you even install the program, there is an S.O.S. diskette to check your machine and disinfect it if necessary. The diskette is bootable, so if you're already in panic mode, or a virus has disabled your operating system, S.O.S. will come to the rescue. S.O.S.'s primary purpose is to check the boot and partition sector, but it also does a rudimentary file scan of your hard disk.
  
• VirusGuard loads into memory during bootup and keeps a beady eye out for viruses while you're in DOS mode. It warns you if it finds anything suspicious, and blocks access to the iffy files. VirusGuard doesn't actually clean out any viruses; it just tells you about them so you can manually invoke FindVirus to disinfect your machine.
  
• WinGuard keeps tabs on your computer while in Windows (including DOS sessions under Windows). In default mode it intercepts executables, macros and assorted program files as you access them. You can extend its reach by enabling various scanning options; Scan on Writes, for example, will scan files you've just downloaded or decompressed. WinGuard will automatically clean any infected files without your intervention, if you choose.
  
• FindVirus is a manual scanner which you invoke as needed. It can scan network connections and searches not only for a long list of known viruses - 15129 at the time of writing - but can also monitor your system for unknown ones. Currently, FindVirus can locate viruses inside ten different types of compressed files. If you're in Explorer, you can also invoke it from the right-click menu for quick scanning of drives and directories.
  
• Regular viruses updates are available, with your first update being free of charge. After this, an Automatic Protection Plan provides monthly updates upon subscription. WinGuard reminds you each month to install an update.