The simplest way (as I haven't Excel available currently, I'm not sure how exactly all steps are done, so maybe you are to adjust somewhat):

Open a new instance of Excel;
From this instance, select Open, set the file type as Text File, and open your text file;
A window is opened, where you can determine the delimiter between columns (comma, or Tab, or Space, or whatever). You also can determine the format of every column you read in (General by default, or Text, or Numeric, or Date, ...). Set your preferences and open the text file in Excel;
In case your table you want to copy the data from text file into is not opened jet, open it;
Copy data read from text file into your table (I advise you use PasteSpecial>Values for this, unless you have set all column formats properly in read-in table),
After data are sucessfully copied into your table, you can close the instance of Excel, used to read text file in, without saving it.