Shoutbox

I have a problem where my computer says i have installed Msn Content Plus when i havent but it says i have to register to it or unistall it, but when i looked in control panel and into Add and Remove Programs the program Msn Content Plus was not there to unistall neither was it in my all programs lst to see if i could unistall it that way. But i waited to the trial day was up which was 30 days to see if would unistall it self but it hasn't and now it pops-up everytime i use the internet and Windows Live Messenger and when i close the alert it closes down both the programs that im using, but now when i use Windows Media Player and Internet Explorer and i start to get a message that comes up sayin "Windows Explorer has encountered a problem and needs to close. We are sorry for the inconvience." and it did the same for Windows Media Player all these problems have started happening since its started to say i have installed Msn Content Plus which i didnt and if it was even accidently installed i cant find it to unistalled can u please help me with this problem.