I am a new user to Mathematica. I tried to using the Import function on a .txt file but failed. The error message reads "Import::nffil: File not found during Import" and is followed by the output "$Failed". Other times the same function fails and the error message reads something like "JPEG filetype not supported". I use Mac OSX and tried converting a picture file to open with mathematica via GetInfo>OpenWith>Mathematica through the Finder window of Mac OSX and the file opens but displays random ASCII characters as though it doesn't recognize the file as JPEG.
How can I import data files saved as ASCII or .xls into Mathematica using the Import[ ] function?