is my computer security at risk?

[KRANTZ]

To make a long story short, sbrugby's AIM got hacked and he had access to some AIM logs leading me to believe it was definitely him. He wanted me to look over some hands and sent them via a .mnr.txt file to my gmail account.

I'm not that naive though and instead of DLing the file I tried to view it as html in the email, and it looked all weird. Before I figured out it 100% wasn't him, I opened it again but this time using the google document application, so it opened it in google docs in gmail. Again, it looked weird. Then he tried to send me a .exe file over AIM and I knew it wasn't him. I never actually downloaded anything, though - just viewed once as HTML and then opened as a google document.

I'm using a Macbook Pro. I'm not too savvy in this area and it would really put my mind at ease if I knew my email/computer security was safe (or give me cause for springing into action if it's unsafe).

Help!