Cyber-Angel you said you ran an anti virus cheek . Did you checked for spyware , malware etc. too?
I use 1 anti virus , 2-3 (not at the same time) spyware programs and one firewall.
These kind of programs are some times commented very differently , but with cautious surfing and so i didn't had much trouble so far .
If you didn't tried , use "Superantispyware" ,"Spyware search and destroy" or any other programs in this kind .
Be careful ! Some look like removers but are spyware itself.
I didn't had such an issue as you had. I don't know if this is any help to you!