From System Tools it states, "Internet Explorer (No add-ons)
I noticed on the blue ball which has the white arroow in the right hand corner has fewer items there now.
It happened when I was on porn sites and clicked on the ads on the side.
I have Windows XP, one meg of Ram I think, can't get the sys info. Sys is near 10 years old I would guess, got the PC second hand. Been working great for a few years.
I use the free AVG anitviral software.