A large misconception when a non runners thinks of the word "Running" they think, miles after miles at lightening speeds". Then they easily get discouraged because they think, "I can't run 5 miles! I can't run 100 meters, I can't run 6 min miles."
Running isn't all or nothing, Its not 5 miles or bust. Its putting 1 foot in front of the other, at a pace faster than speed walking, for whatever amount of time you want. There is no judge, only yourself.
Dont focus on "can't run # miles". Instead break it up.
Do 1 mile in the morning and 1 mile at night. Or even break it up until 3rds. Morning, Noon and Night.
You're working on building up the muscles in your legs. Once your legs get stronger, you can then work on building endurance, by extending the distance of each segment and then cutting down the # of segments. Then once you get your endurance up, you can focus on speed.
This is also a great method for runners recovering from injuries.
Instead of running 6 miles, run 3miles in the morning and 3 at night, or 2 miles Morning, Noon and Night.
Start of slow, in small segments and you'll reach your goal.