Securityhelpcenter.com is a browser hijacker promoting the rogue anti-spyware application Personal Antivirus. Typically your computer becomes infected with a backdoor trojan that modifies your browser settings in order to redirect you to the Securityhelpcenter.com domain. Usually, though, when you attempt to visit certain websites, Securityhelpcenter.com redirects you to this warning:
"Warning! Visiting this site may harm your computer! This web site probably contains malicious software program, which can cause damage to your computer or perform actions without your permission. Your computer may be infected after visiting such a web site. We recommend you to install (or activate) antivirus security software."
This is when you are suggested to purchase and download Personal Antivirus in order to protect your system from infection. Unfortunately, Personal Antivirus is an infection in itself, and should be avoided.