Rekindle the failed purpose
While researching how to get things done (as part of the organizational philosophy of Scientology) L. Ron Hubbard hit the problem of mankind's tendency to stop things. For example stressing what shouldn't be done rather than what should be done - most laws epitomize this.
From this research he discovered that behind every stop there is a failed purpose. An example of this was a friend of mine who just couldn't seem to have a successful relationship, everything he did in the area seemed to hit a barrier - a stop - and he was very apathetic about the whole thing. When I was helping him it turned out that he'd had the purpose to have a successful marriage but his first marriage had failed dismally.
The solution? Mr. Hubbard discovered a law - "All you have to do to restore life and action is to rekindle the failed purpose. The stops will at once blow." ("blow" = go away). I had my friend look at his original purpose and times when he'd had success with it and he once more got the idea that the purpose could be attained. Within a week or two he was dating and a year later had remarried - a big improvement over 3-years of nothing happening.
The data on failed purposes can be found in Organization Executive Course Volume 0.