Computer Hijacking Via an ISP & IP Address.Is This Now Possible?

Hello.Has a way been found whereby a UK company can now e-hijack your IP address just for visiting a website?For example,in April,I entered an adult entertainment website.As I clicked out of the site,and without clicking to accept any of its services,I found I had suddenly got a 3 day trial period which then led to a �19.99 a month bill.Over a period of a few days,this bill would keep reappearing and effectively 'strangled' my computer every time it came up until I 'coughed up'. I downloaded Prevx and AVG software which found sware galore issued by this firm. By getting rid of this sware,I was able to gain control of my computer.It seems that on certain adult entertainment websites,all you have to do is look over the first page.As you exit,the website automatically sends sware to hijack your computer.Once in the computer,and everytime you're online,the two link up and create havoc with the computer.Any help would be gratefully accepted.Thank you all very much for your help.