
Worms is factor that can damage your computer because it make copies on a local drive and reproduce themselves again and again. When it replicates, it takes a lot of space in the hard drives that made the pc too slow. Another factor that can also harm is the most common that we had encounter, the viruses. This might corrupt or delete data on your computer. Virus is more dangerous than a computer worm as it makes changes or deletes your files while worms only replicates itself with out making changes to your files/data. Trojan can also damage your computer because it looks like an application, they do not replicate themselves but they only destruct.
So before you download anything from internet be sure about it first. Almost all viruses are attached to a file, which means the virus may exist on your computer but it actually cannot infect your computer unless you run or open the malicious program. It is important to note that virus cannot be spread without a human action, such as running an infected program to keep it going.