听力原文：W: My computer has a problem. It doesn't scroll down any faster whenever I am using a word processor.
M: Well, then have you checked for any viruses recently？ Sometimes, if you don't have it periodically checked and let the viruses build up, the computer slows down or doesn't reboot.
W: Wow! How do you know all those things？ I wish I could do a lot more with my computer and do it faster.
M: Then why don't you visit the computer center？ They will teach you how to deal with any basic problems you might suffer from malfunctioning computers.
What is the conversation mainly about？

A. Some recent cold symptoms.
B. Computer virus protection.
C. Taking college classes.
D. An electronics store.