I have just done a scan with Microsoft Security Essentials last day and apparently it got detected a trojan, so I clicked on clean computer. After that some time later I popped up with continous warning that there is a trojan virus in my system. I had scanned back and a trojan is detected. I scanned my system back but this virus is still in the system. I was downloading a video clip when the virus entered the system. Now it has also blocked Internet Explorer. It is not working at all for online scan.