Installed the office 2010 application on my windows 7 system last month. It ran without any sort of problem till yesterday when i was trying to open a word file which was mailed through the internet via one of my friend. Whenever i click on the word document i get message "Some files contain viruses that can be harmful to your computer. It is important to be certain that this file is from a trustworthy source." can any one tell me how to go about this problem.