It's Spyware.
Spyware can hide itself anywhere on your computer
folders,links,favorites,programs,pop up's,ads and toolbars(like The Guffins, Cursor Mania ,Smiley Central and Zwinky)Most of toolbars are low level Spyware
I hope that helped.
The Macro virus is the most common type of computer virus. The ILOVEYOU virus is one example of this type of virus which hides in a document or spreadsheet.
Boot Sector Virus
Computer viruses that hide in or disguise themselves as a useful executable program are called Trojans. These types of viruses are very dangerous because they are hard to detect and can gain complete control of your computer when you run them. To avoid this type of virus, be careful where you download software from. Even legitimate programs can be modified to have Trojans hidden in them.
There are many threats that can be found on email. One of the most Computer Virus that sent via email is the "Email Virus". This is a script, code, or an application that will alter a process, code or another program. Since some of them are script, they can enter beyond the field of Antivirus without being quarantined. Another one is the Phishing scam. This is not a computer virus but this is a security threat. It allows user to click links and type email. But behind these links are process that traces ID and other personal stuffs.
a type of disraction which makes your computer slow
The virus is build to only react when it comes in contact with a certain type of antigen, let's say the surface of a certain cell. The virus will then inject his RNA or DNA into the cell which gives the cell instructions to build more virus particles.
It's a virus and steals your secret credentials. It hides as an 'anti-virus' but in actual fact slows down you computer and sends usage tracks (what you've been doing) to it's host. This type of virus is called a YUSTEWPD (Yolgankovic Unit Stealing Technolgical Endager Wandering Program Destroyer). Use your antivirus to remove this immediately.
Mainly Trojans and Worms, but some can happen without even booting it.
virus
a virus could also be a worm, trojan, etc.
The Ebola virus
A program or script