I was working on a problem from which I copied a portion of my work to send to a friend through e-mail. Two things happened.
When I copied into e-mail mesasage no part of the notebook copied over.
Then, I sent a portion of the problem as an attachment through e-mail. When I open up the notebook which I had been working on the notebook freezes when I get to the point in which I copied and pasted, then the whole system freezes on me. Since that time, my program freezes up on my and I cannot use Mathematica.
Any suggestions about what is happening, how to avoid this in the future and what this means are appreciated. TIA.