I dont know what this is, please help

Today I turned on the computer and did a bit of browsing, all sites in which I go to on a daily basis. they belong pretty much to youtube, easyphpbb, and userplane.

When i was in user plane chat, this windows installer box appeared, and said something about updating windows office 2000, i clicked cancel, and it kept on trying to do it. Re appearing, then saying some error message about it not being able to uninstall without the CD for office.

I quickly went to adaware, but had to install the new version, then as it was scanning, whatever I clicked on, the task bar, yahoo, internet that damn thing kept trying to pop up and install something.

Then when i'd open my firefox, there was a photo of guitars and guitar pedals and things, I dont know what the address was but it was something like www.knockout/something or other.

Adaware found nothing. My AVG has found nothing. Yahoo flashes around in the task bar, it seems to come when i try to open yahoo and send a message to someone, or it could be cause i'm double clicking, i'm not sure.

Can anyone tell me what this is and how to fix it?

 

i don't remember which site it was but i got an ad pop up about system security i did not open it but canceled it immediately at some stage later in the day i started getting pop ups to say my computer is infected and to down load a program to solve the problem and no matter what i did these pop ups returned in the end i did the malware clean

http://forums.majorgeeks.com/showthread.php?t=106650

and it got rid of it maybe the virus idiots have found a new way to infect us.

 

Yesterday a friend got me to get rid of AVG and go with Windows LIve One Care.

It seems to have done the trick, it blocked something called, "Bonjour something"

When reading up on it, i didn't find much about it being a virus, but that it's something to do with apple software.

The antivirus did remove 2 infections that AVG did not find. Maybe it was in that, but I think the Bonjour thing is still there, cause when I first ran it, it said it blocked it from getting through the firewall.

So i'm not sure if one of those 2 virus' it removed was what was causing me this problem, or if blocking the Bonjour thing has fixed it.