sites in my history that I did not visit

[hanamontana]

Hi,

Recently, I have found some websites in my history which I never visited, might this caused by a kind of virus, actually the sites are so embarrassing and bad. No one used my computer. the websites are: bearwww.com & silverdaddies.com I think, and there were around twinty pages visited in the history at certined times. could this be a virus or my network was hacked by some body, I use Avast anti virus and do not but a firewall. please tell me if this could happen without visiting such these bad websites.
Hint : the fisrt website ( bearwww.com) was able to be opened at the moment I found it in the history, but when I delete the history and tried to open the site again, I was not able to as they say I should have a profile to enter the site parts.

Thanks alot

[CimmerianX]

Do you have anti malware installed? Might be a good idea to run a full scan. I use malware bytes. It's free and excellent. IF you use that, install it, run the updates, and opt for a full scan. It will alert you if it finds anything.

[JorgeM]

Also, some AV endpoints include URL filtering. NOt sure about avast. You could also try Blue Coat's K9 free client. It will block sites based on categories, including malicious and suspicous sites that are known to infect visitors.