Internet Connection Problem

I recently encountered a virus on my Dell Studio laptop which I got rid of using MalwareBytes software. This eliminated all the annoying pop-up messages and blocked applications. However, since then I have been unable to use any application that accesses the internet (other than Firefox for some reason). Applications like iTunes store, Internet Explorer and Google Chrome are all unable to display web pages. My laptop also is now unable to download Windows updates as it cannot access the internet.

I've checked all of the programmes that are blocked by my Firewall and these are all checked as allowed programmes. I've tried restoring my laptop to a previous point where it was functioning properly but this has no effect on this.

Also I'm not sure if this is related but when I restart my laptop, I get the error message that "STLog.dll" cannot be found and that the ST service is unable to run.

I've tried restoring this file using the method recommended by Microsoft (a programme called "MicrosoftFixit50203") but this hasn't solved the problem either.

I'd really appreciate your help with this problem!

Thanks