Have I got the virus? I have Google Nexus 7 tablet for some time and I recently noticed that I have file named "Designing for android.pdf" in "Download" folder (native OS folder) . Now problem is that I never downloaded this file ever, since I am not android app developer and neither I have plan to do it any sooner. 

Anyways coming back to it, on top of that whenever I try to open that file using , Adobe reader, Native one (I just get the option which app to use to open the file), and Kingsoft office viewer, none can open the file reporting different errors like file is corrupted etc.

So is this file malicious? Anyone reported of any malicious file having name similar to above file? or OS itself distributes it as it's part?
If you think this file is not pdf.. then downlad it on windows pc and open by notepad. First few letters in first row will tell you what format is current file. You can paste it here to let us see what is that.

For example:


  %PDF-1.6