I am infected with a browser hacker virus for a day now. It probably came from a software called YuoTubeDownloader. I cannot uninstall it and I also have an extention in firefox called YuoTubeDownloader 18.104.22.168. I cannot disable it either. It re-enables itself after I start firefox the next time after I 'Restart now' when I disable it. I have scanned my computer with Bitdefender Internet Security 2011 but it didn't find any viruses. I also have a free version of MalwareBytes AntiMalware but it didn't catch any viruses either. I had even updated both the softwares before scanning. I don't know what to do. I don't want any information to be compromised from my computer. I am using Windows 7 Professional 32-bit version. Please help!