Worm:A worm is often characterized as a malicious application that will use a host machine to infect other machines. Therefore worms can create enormous damage on networks with multiple computers.
P2P-Worm.SpyBot is a nasty worm that propagates via Peer-to-peer sharing network, through various browser vulnerabilities and Trojans. Once executed, P2P-Worm.SpyBot will hide itself deeply in the system and add 2 registry keys so it can launch on each Windows startup. Then, P2P-Worm.SpyBot will open a backdoor through which a remote attacker may get a full control over your PC and steal your personal information.
Technical details (How to remove P2P-Worm.SpyBot(pop up))