Looking back to this thread, Mike brought up what is written through experience.
i was just spouting off and failed to give this the full details. Sincere apologies to anybody who thinks it might be just that simple, because usually it is not.
There is a type of fasting effective in this that will bring the gates of hell crashing down.
When fasting is stated, this only has to do with abstenance of food and self-denial in principle alone, and not neccesarily in the actual exercise of doing that activity.
It has more to do with turning the other cheek and returning good for evil. In this, you stand in antipathy against the spirit that's causing the trouble.
Ask God to show you the type of spirit that is causing the trouble, and do the exact opposite yourself. For the evil that it does, you do the good thing in opposition to it's activities in return.
There are those who think speaking the name of Jesus is the end all, yet if we have areas in our own life that are relative to the spirit being stood against, we lack the neccesary purpose of this authority to stand against it.
For example:
I could be a police officer dressed in full uniform and on duty, and in pursuit of an offender, shout out "Stop, in the name of the Law" and would be walking in the power, purpose, and authority of the Law to maintain peace.
Let's say i am that same police officer, at 3a.m., drunk as a skunk, totally disoriented, go to a door of a house that i thought was my own, knock...but can't get in. The person inside says that i need to leave before they call the police. So, i holler out, "open up in the name of the law," brandish my issued weapon...
...and land in jail.
Understand the implications of what is being done and the stance on your part to be assumed. Trust Jesus to make you unwavering in both returning good for evil (in denying yourself and ways), pray in this authority...
...but first, pray: ask God to show you what's what and then interceed.
Intercession is physically manifested in returning good for evil.
(from here, it 'usually' is a very small matter of telling the spirit to cease, desist, and scat for good.)
Hope this is better help.
Sorry for the tert answer at first.
(i should know better.)
To you:
God's grace and shalom
in and of Jesus Christ,
g