Some Types of Ghosts....

The word poltergeist comes from the German words poltern ("to make noise") and Geist ("ghost"), and the term itself literally means "noisy ghost".
  Most reports of poltergeist manifestations involve noises and destruction that have no immediate or verifiable cause. Situations include inanimate objects being picked up and thrown; noises such as knocking, rapping, or even human voices.
 Poltergeist are also known to hurt humans but is a very rare occurrence.
 To my friend that spoke of some things going on in her house ;)....  I trust this is what your dealing with. And ignoring it is the best thing in fact showing it attention may make it more active then again it could be a deceased person wanting prayers to be released we never really know but theory's are many and make scene. This may help a bit to understand it:

The key here is the word "manifest": souls of the departed come to us in many ways, especially in dreams. They try to remind us. They seek our help -- and later they help us. But we have to be careful. Moreover, we have to be careful because demons can mimic the dead in order to gain entry. Many are the "haunted" homes that are actually plagued by evil.

Thus, if we have a manifestation, the first thing we should do is use Holy Water and Blessed Salt or whatever means of a ceremony to do with GOD, and cast out any potential evil with fervent prayer. We do this not as an exorcism (which should only be handled by a priest), but as a deliverance -- and only in the Name of Christ. If that doesn't work, we should have a Mass said in the home, and especially for any deceased who may be connected with the disturbance. While we do not have the authority to cast out a purgatorial soul (as we do a demon), our praying for them often causes their release. There may indeed be souls who haunt places because they are trying to get prayers and also those who died traumatically or are obsessed with a former residence or some other aspect of material existence.

The month of November is set aside as the month to pray for the dead, and we urge this. We urge it especially for those who have died recently, or those who we have seen in dreams; for those who may have no one else to pray for them. If you do this you'll find joy and often release in your own life! And if there is a disturbance -- if there is such a thing.