Avast removed infected switchboard.exe then after rootkit scan no internet

Hi

I’m running Windows 7 SP1. My computer had been running incredibly slow for a couple of days when Avast found a Trojan which had infected switchboard.exe. Stupidly, I did not note the name of the Trojan and simply pressed delete. I was trying to load google.com at the time. Avast recommended running a scan of the MBR so I restarted the computer then the scan completed then the computer shut down. When I started it again I had no internet access and required administrator permissions to change settings.

I´d appreciate any help or advice you might have.

I've reformatted and reinstalled the OS that seems to have fixed it. No further help needed. Thanks