Hi Paul
Your PC has an extremely nasty infection
win32.polip. Disconnect it from the internet and your network
NOW.
Uninstall all cracked software and obtain a liscenced anti-virus program to scan your other computers.
AVG Anti-Virus
Avast Home Edition
Scan all the other computers with updated virus definitions. If all of the computers are infected with win32.polip then I would advise full re-installation of Windows on all computers. The drives should be fully formatted with the manufacturers disk tool or a third party disk wipe utility before attempting to re-install the Operating System.
This infection is transmitted via P2P networks and injects malicous code into many important system files and program files. Cleaning of this type of infection is difficult and may still result in a full re-install being required. The best way forward is to re-install now rather than attempt cleaning.