Antivirus: - install an antivirus before using internet connection। An antivirus keeps your computer safe from unwanted programs which can damage your computer. There are so many antivirus programs available in market. You have to choose the right one according to your computer specifications. Some of the good names in antivirus programs are Norton, McAfee, Webroots etc.There are so many free antivirus are also available.After installing a antivirus program one must update the antivirus time to time. If your antivirus is not updated time to time then virus can spread even the antivirus is installed.

Firewall:- Firewall is the security guard of your computer while using internet connection. It restricts the unauthorized entry from outside to your system. You can setup personal security settings by using a firewall program. There are so many Firewall programs are available in market choose the right one and install it before using internet connection.Firewall program is of no use for stand alone systems without internet connection. There is no need to install firewall for them.
Emails:- Every one who is familiar with computers is using email accounts for communications .But now a days most of the virus programs come through e-mails. This is the easy way to spread virus. Before opening an attachment with e-mails make sure that it is of your use and comes from your known persons. Most of the time attachments with unknown extensions are virus programs which can damage your computer. If mails with attachments comes from unknown persons then don't try to open or save them on your computer they can be virus programs.
Some general instructions for the use of computers1। Shutdown computer in proper way.2. Close all the applications before doing shutdown or restart of your computer.3. Make your electrical connections tight for computers.4. Do not place magnetic things near to your PC these can affect your PC.5. Do not use pirated software’s for your PC.6. Always scan the floppy or CD with antivirus before opening them in PC.7. Always use Uninterrupted Power Supply (UPS) for your PC.8. Keep your PC away from dust and heat.