Most likely you ended up with text in the "Normal" template.
In Word, use the File->Open and navigate to (your home)/Documents/Microsoft User Data. There is probably a file named "Normal" in there, open it.
If what comes up is the text you have been seeing when creating a new blank document, you have found the problem. Quit Word, drag that file to the trash, and restart Word. All should be back to normal.
If you have set up custom margins or fonts and want to keep them, an alternative approach would be to open "Normal" as above, delete the text, and save it so that new documents will still use those settings.