I'm new at computer.When I open the file where I have mobile videos it get...

[bill_gr]

...me out of windows.What I have to do I recently bought a computer and every video on my mobile phone I put it in a file.One day when I opened the file it get me out of windows saying that "the explore of windows stops working" and returned me at working surface.Since then every mobile video I put in any file, new or old, it is happening this. I noticed that there are some files named NTUSER.DAT and I cannot delete them. What I have to do and are these files the reason that it is happening this? Thank you very much.