Miranda

Can anyone please help me. I went to a site and when I left it, I got a popup that is asking to change my homepage. I say no, and the popup wont go away. It has highjacked me to their site which is called about blank and it is a search page with spyware advertisements. I ran adaware and spybot, and it wont go away.
I have completey shut down and rebooted and the popup still comes up.
Anyone have a fix, I would certainly appreciate it.
Thanks in advance
Miranda