Win32.Ishbot is one of the many pervasive backdoor Trojan programs out there that will enter your PC without your permission and without notification. It is able to do this by masquerading as another program or you could have inadvertently added it from downloading a freeware or shareware program. They will often come bundled with such programs and you may infect your machine without even knowing it.
Remove at once
To be sure you are fully protected, you should try ZookaWare PC Cleaner. ZookaWare PC Cleaner has been on the market for many years and has been trusted by thousands of customers. Backed by an unbeatable money back guarantee and the Better Business Bureau, you can feel safe with ZookaWare PC Cleaner.