A customer came to the internet shop and told me of the problem with his laptop. He used his pendrive to save a file at his college computer. When he connects the pendrive to his laptop, he is unable to view his C and D drive. His other friends who used the college computers were facing the same problem. They tried their best by scanning for viruses but to no avail. A few of his friends had to reformat the whole harddisk because of that problem.
I checked all the programs in the laptop. He is using one Norton Antivirus program. There are no other security programs beside the antivirus program. He should have use ESET antivirus program. Furthermore, there are other essential programs that every computer should have such as anti-spyware, firewall, and anti-exploits programs. However since there warranty is still applicable, I advised him to send the laptop back to the dealer.