You don't need to delete the whole Family Tree program. The simplest method is to go to the "File" drop-down menu (top left) and select "New". You will get a prompt to enter a name for your new file (must be different from the original one), and you can then start entering your corrected data in a fresh file.
You can either leave your original file (complete with erors) as a kind of reference, or delete it once you're happy with the new file. FTM 11 lets you have 2 files open at once for comparison, which can be useful.
If you decide to delete the original file, open the new file and close the old one. Then use the "File" menu and select "Open": you should see a list which includes both your family files. Select the old one, but instead of clicking on "open", hit "delete" on your keyboard - this will do the trick.
Hope this helps!
Rambler
