Run the Internet Connection Wizard. And use Avast or Antivir instead of AVG. The free version lacks rootkit protection, and if there's anything you want to keep off a machine, it's rootkits.
Start the machine in safe mode or using Last Known Good Configuration; click here . Disconnect machine from the internet.
Download Malwarebytes Anti-Malware ( click here ) and latest definitions ( click here ), burn to CD or put on a flashdrve. Run the installer on the problem machine but choose not run the actual program immediately. Run the mbam-rules.exe file to update the definitions. Then run a full scan with Anti-Malware. Yuu can download SuperAntispyware and its definitions too if you'd like to scan with both. File; click here
Definitions; click here