Hello!  All computers come with a Trial version of Microsoft office unless you purchased a copy during the purchase of your X51.  If your trial copy has expired, you will have to buy a license in order to use it. 
hi,  was happened 8 months ago, I did bought alienware x51 desk, at that time I was not in used of Microsoft office, and now when I was going to use It saying that my trial had been expired.  was that my x51 didn't include Microsoft office full version from the time I buying or? any way to get Microsoft full version on my x51 ? am really tired of seeing those expired. 
Microsoft office only trial version?