Metatrader was created by MetaQuotes
http://www.metaquotes.net/Guess you know that already but just posting it here for reference should somebody else might pickup on the 'metatrader' part.
There is only two places from where you should download Metatrader and that is from MetaQuotes and or your broker's website. Also be very careful with downloading indicator and or expert advisor files for this platform especially if from unknown sites. If you do check them with a virus scanner first. These indicators and or expert advisors (EA's) can be coded to call dll files and many other things so will not be surprised either if this route is followed to slip something onto pc's.