What is a computer virus?

 A computer virus is a type of malicious code or program written to alter the way a computer operates and is designed to spread from one computer to another. A virus operates by inserting or attaching itself to a legitimate program or document that supports macros in order to execute its code. In the process, a virus has the potential to cause unexpected or damaging effects, such as harming the system software by corrupting or destroying data.

What are the signs of a computer virus?

A computer virus attack can produce a variety of symptoms. Here are some of them:

• Frequent pop-up windows. Pop-ups might encourage you to visit unusual sites. Or they might prod you to download antivirus or other software programs.
• Changes to your homepage. Your usual homepage may change to another website, for instance. Plus, you may be unable to reset it.
• Mass emails being sent from your email account. A criminal may take control of your account or send emails in your name from another infected computer.
• Frequent crashes. A virus can inflict major damage on your hard drive. This may cause your device to freeze or crash. It may also prevent your device from coming back on.
• Unusually slow computer performance. A sudden change of processing speed could signal that your computer has a virus.
• Unknown programs that start up when you turn on your computer. You may become aware of the unfamiliar program when you start your computer. Or you might notice it by checking your computer’s list of active applications.
• Unusual activities like password changes. This could prevent you from logging into your computer.

WHAT IS CMD

Command Prompt is a command line interpreter application available in most Windows operating systems. It’s used to execute entered commands. Most of those commands automate tasks via scripts and batch files, perform advanced administrative functions, and troubleshoot or solve certain kinds of Windows issues.

Command Prompt is officially called Windows Command Processor, but it’s also sometimes referred to as ​the command shell orcmd prompt, or even by its filename, cmd.exe.

Command Prompt is sometimes incorrectly referred to as “the DOS prompt” or as MS-DOS itself. Command Prompt is a Windows program that emulates many of the command line abilities available in MS-DOS, but it’s not MS-DOS.

How to Remove Virus Using CMD

Now, follow the steps below to delete viruses from your computer or storage device using CMD.

Step 1. Type cmd in the search bar, right-click “Command Prompt” and choose “Run as an administrator”.

Step 2. Type F: and press “Enter”. (Replace “F” with the drive letter of the infected partition or device.)

Step 3. Type attrib -s -h -r /s /d *.* and hit “Enter”.

Step 4. Type dir and hit “Enter”. Now you will see all the files under the assigned drive. (The dir command displays a list of a directory’s files and subdirectories.)

Step 5. For your information, a virus name may contain words like “autorun” and with “.inf” as the extension. Thus, if you find such suspicious files, type del autorun.inf to remove the virus.

Here are the basic attributes of the ‘attrib’ command:

R – represents the “Read-only” attribute of a file or folder. Read-only means the file cannot be written on or executed.
H – the “Hidden” attribute.
A – stands for “Archiving” which prepares a file for archiving.
S – the “System” attribute changes the selected files or folders from user files into system files.
I – “not content indexed file” attribute.

The “attrib” Syntax:

ATTRIB [+ attribute | – attribute] [pathname] [/S [/D]]

In the above command, let’s see what the different parameters and switches are:

‘+ / –’: To enact or to cancel the specified attribute.
‘attribute’: As explained above.
‘/S’: Searching throughout the entire path including subfolders.
‘/D’:  Include any process folder.
‘pathname’: Path where the target file or folder is located.

Here is the proper syntax order for attrib command:

ATTRIB [+R | -R] [+A | -A ] [+S | -S] [+H | -H] [+I | -I] [drive:][path][filename] [/S [/D] [/L]]

If you receive the message “Access denied”, you should:

• Make sure you have run Command Prompt as an administrator
• Make sure the file/folder is not in use
• Check the permission of the current account and make sure you have full control over the file/folder (right-click the file/folder/partition and go to “Security”)

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