error message everytime i open a window in vista

first of all i kmust say I take all responsabilities for this problem i did not check for viruses or spyware when i downloaded a aplication and this is what i get for being stupid

so the problem is that after i opened the file i downloaded i looked at my user files and a window opend telling me that i was infected by a virus and that a need to download a virus from internet

when i press cancel the page goes away but opens when i try to open another window
when a press ok it sends me to a wep page to download a file

from this site www.ieantiavdownload.com

can someone help me with this please

i scaned my computer with these aplications

spybot
avast 4.8 free edition
nod32
and windows defender

i also looked at my task manager to see whats programs are running but nothing



need help thanks

Attached Images

error message.jpg (95.3 KB)