intriguing things happening with my PC

Hi,

I’ve just opened another window because I wanted to log in to my hotmail account.

From the homepage, I hit the down arrow on the address field, which I usually do, then scroll down and select http://www.hotmail.com

However, I’ve just clicked on the arrow and instead of my usual list of websites that I visit quite regularly, all of a sudden there’s a list of websites I’ve never visited, including:

gallview.com
bimbo-sex.com
spermdrops.com
cunt4all.com [excuse the language here, but that’s what it says]
tweaksex.com/tgp.shtml

Can any of you techy peeps tell me what’s happening with my computer? BTW, it’s my home computer and no one else uses it without me knowing.