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Showing posts with label Computer education. Show all posts
Showing posts with label Computer education. Show all posts

Sunday 17 September 2017

What are the top 10 computer viruses of all time?

What are the top 10 computer viruses of all time?


Viruses come in many forms and are created with different intentions. Some corrupt or delete a computer files while others are designed to replicate until they use all of your RAM; rendering your computer unable to operate. There are even viruses, like Ping-Pong that are created as a joke and do not cause any real damage.


To date, there have been over one million computer viruses created, but only a small percentage of them are in mass circulation. Only a few have created havoc and fiscal cost at the level of those viruses listed on this page.


Ten of the most prolific viruses of all time


1. Storm Worm (also called Peacomm and Nuwar) - On January 19th, 2007, over 200 million e-mails included links to download the Storm Worm, which help play a part in the overall attack. Most believe the worm gets its name from the fact that one of the e-mail messages carrying the virus had "230 dead as storm batters Europe" as its subject.


  • Different than the W32.Storm.Worm released in 2001, this virus was released and identified in late 2007.
  • Allowed hackers to control the computer remotely, using it for malicious activity, like sending mass amounts of e-mail (spam).
  • Propagated through fake links to videos and news stories.

2. Netsky and Sasser - Netsky spread via e-mail and Windows networks, creating large amounts of Internet traffic and causing Denial of Service (DoS) attacks. At the time, Netsky and all its variants were believed to have accounted for as many as 25 percent of all computer viruses on the Internet. Sasser replicated by finding other systems with vulnerabilities and forcing them to download the virus. Once it was on a new machine, it altered the operating system to make it difficult for users to shut down their computer.

  • Released in February and April 2004 respectively.
  • Created by 17-year old Sven Jaschan.
  • One of the few viruses to be tracked back to their creator.
3. MyDoom - This worm was unique in that it had a timer of sorts. The virus created started Denial of Service attacks, then stopped distributing itself 11 days later. These attacks were aimed at various Internet servers, including attacks against search engines, causing several of them to crash and others to return search results much slower than normal.

  • Released on February 1st, 2004.
  • Replicated using e-mail and peer-to-peer networks.
  • Created backdoor that stayed open even after the worm stopped distributing itself.

4. Blaster Worm - This worm was unique in that once it got onto a network, it spread quicker because firewalls typically did not prevent internal machines the port it utilized. It was stopped by filtering by ISPs and public awareness.

  • Released in August of 2003, original creator is unknown.
  • Infected millions of computers worldwide.
  • Launched Denial of Service (DoS) attacks against Microsoft servers.

5. SQL Slammer - A prolific web server virus, the Slammer (also known as Sapphire) infected nearly half of the servers that help run the Internet 15 minutes after its initial attack.


  • Released in January 2003.
  • Affected computer networks and systems, causing shutdowns and a range of damage estimated at over $1 billion.
  • Caused Bank of America ATM service to crash, interruptions in Seattle's 911 service, and more.

6. Nimda - Spreading through e-mail and Web pages, this worm targeted Internet servers, slowing Internet performance nearly to a halt. It also opened a backdoor to the computer's operating system, allowing a hacker access to the computer. However, access was limited by user account permissions.


  • ​​Released in 2001.
  • Name is the word "admin" spelled backward.
  • Fastest spreading computer virus in history.

7. Code Red / Code Red II - These viruses exploited a vulnerability in Microsoft Windows 2000 and NT, causing a buffer overflow. Code Red initiated Denial of Service attacks against White House web servers, while Code Red II opened a backdoor for hackers to access Windows 2000 systems.


  • Released in summer 2001.
  • Later blocked from spreading by Microsoft patch.

8. Klez - This virus was unique in that hackers reproduced in many forms. It was also capable of spoofing; which helped spread the virus as recipients would think it was coming from a friend.


  • Released in late 2001.
  • Distributed through e-mail.
  • Capable of disabling anti-virus programs and making a computer unusable.

9. ILOVEYOU - Traveled through e-mail as a message from a secret admirer. When users downloaded the attachment called WIN-BUGSFIX.EXE, the virus would copy and embed itself in key files; including Registry keys.


  • Suspected to have been created by Onel de Guzman (Philippines) in 2000.
  • Initially spread through e-mail and later through IRC clients.
  • Damage caused by the virus was estimated at around $10 billion.

10. Melissa - Once activated, the virus would replicate and then sends itself out to the first 50 people in the address book of the recipient.


  • Created by David Smith in 1999.
  • Created a mess for government and public sector networks.
  • Caused some e-mail providers to shut down e-mail services until the virus was contained.


Tuesday 25 July 2017

Mozilla Firefox shortcut keys

Below is a listing of all the major shortcut keys in Mozilla Firefox. See the computer shortcut page if you are looking for other shortcut keys used in other programs.


Shortcut Keys                            DescriptionF5                                   Refresh current page, frame, or tab.
F11                                 Display the current website in fullscreen mode. 

                                      Pressing F11 again will exit this mode.
Esc                                 Stop page or download from loading.
Spacebar                        Moves down a page at a time.
Alt+Home                       Open your homepage.
Alt+Down arrow              Display all previous text entered in a text box 

                                      and available options on drop-down menu.
Alt+Left Arrow                Back a page.
Alt+Right Arrow              Forward a page.
Ctrl+(- or +)                    Increase or decrease the font size, pressing '-' 

                                      will decrease and '+' will increase. Ctrl+0 
                                      will reset back to default.
Ctrl+D                            Add a bookmark for the page currently opened.
Ctrl+F                            Access the Find option, to search for any text 

                                     on the currently open web page.
Ctrl+H                            View browsing history.
Ctrl+I                              Display available bookmarks.
Ctrl+J                             Display the download window.
Ctrl+K or Ctrl+E               Move the cursor to the search box.
Ctrl+L                             Move cursor to address box.
Ctrl+N                             Open New browser window.
Ctrl+O                             Access the Open File window to open a file in Firefox.
Ctrl+P                             Print current page or frame.
Ctrl+T                             Opens a new tab.
Ctrl+F4 or Ctrl+W            Closes the currently selected tab.
Ctrl+F5                            Refresh the page, ignoring the Internet cache 

                                      (force full refresh).
Ctrl+Enter                        Quickly complete an address. 

                                       For example, type juicerecipesonline in the address bar 
                                       and press Ctrl+Enter to get https://www.juicerecipesonline.org
Ctrl+Tab                           Moves through each of the open tabs.
Ctrl+Shift+Del                   Open the Clear Data window to quickly clear private data.
Ctrl+Shift+B                      Open the Bookmarks window, to view all bookmarks in Firefox.
Ctrl+Shift+J                      Open the Browser Console to troubleshoot an 

                                        unresponsive script error.
Ctrl+Shift+P
                      Open a new Private Browsing window.
Ctrl+Shift+T
                      Undo the close of a window.
Ctrl+Shift+W
                     Close the Firefox browser window.
Shift+Spacebar
                  Moves up a page at a time.


Related Searches:)


Top 10 keyboard shortcuts everyone should know.
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Keyboard

Tuesday 24 January 2017

What is a PC?

What is a PC?


The letters 'PC' stand for 'personal computer' – that is, a computer that can fit on a single desk for use by ordinary people, as opposed to a huge mainframe or supercomputer.

Although the acronym technically refers to any such computer, it has come to mean the multi-purpose machines that usually run the Microsoft Windows operating system, as opposed to the Macintosh machines made by Apple.

Key benefits and features of the PC


PCs used to be known as 'IBM-compatibles' as they were based on systems built by the IBM Corporation. However, the machines went on to be made by so many other companies that the term fell out of use – in fact, IBM has completely stopped making PCs.
PCs are mainly identified by their use of the Windows operating system. An operating system is the background software that runs everything else on top of it. Windows is the best-selling 'OS' in the world.


Windows is not the only OS that PCs can use. Linux is a free 'open source' system that has been created by volunteers around the globe. It's very popular among the technically minded, but is unlikely to suit a beginner.
 

PCs are capable of many functions, including word processing, playing music, videos and games, accessing the internet, and much more.
 

PCs have a number of advantages over Apple Macs: They're generally cheaper, they have far more software available (especially games) and, as they're more popular, they tend to have fewer compatibility problems on the internet. They're also much more open to tinkering, if you're so inclined.
 

The PC's Achilles heel is its vulnerability to all sorts of viruses and malware. So far Apple Macintoshes have proved to be much more resilient against viruses and other threats. 

With a PC, you can't afford not to invest in antivirus programs and keep them up to date.

Good Morning Beautiful

Do you know????

Do you know????
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