maybe...maybe not
1.Tell me what the file was...was it called like "dupeswap2.exe" or what?
2. Did you run any of the programs
3. you say you only play open, so you dont play closed bnet? if so then your diablo is safe, no one cares about open.
4. IF it is a trojan, you still need to clean it out usin the sticky, because well...ya.
:EDIT: just read your new post, norton sux, trust me, nortan wouldnt know it if a virus walked by and smacked it in the face.
:EDIT 2: whatever you do, DO NOT run the program if you havnt already.