activesearch.com has hijacked your browser. Some companies think that changing your browser from the page you use (and so presumably like) to another page of their choosing is a brilliant way to advertise their web site. Er, NO!
Some companies even use some persistent code which makes it quite difficult to change your browser's homepage back to the page you want. Hopefully this is not the case.
I've assumed you use Microsoft Internet Explorer as your browser...
Click on Tools in the Browser's Menu Bar, then select Internet Options.
In the General Tab you will see a field titled Address. Type in the URL of the homepage you want. (For example www.google.co.uk)
Lastly, click the OK button.
I hope this works and that activesearch.com never bothers you again.
Kaz-K
December 2003