Spirit Guides are very different from Spirits and people and pets that have passed over to The Other Side. Can Beings that have passed away be Spirit Guides? Oh, sure but they can also be lost, confused or even controlling. Your Spirit Guides can also be your Past Lives or Beings from 'other' places, dimensions or levels of consciousness. And those Past Lives and Beings could also be Spirit Attachments mistaken for Spirit Guides.
Psychic Tip: Anytime you want any Guidance [from other than yourself] always, always say or think something to the effect of, "All the Information Must Come Through My Higher Self." It's kind-of a catch-all. Plus, it keeps all kinds of critters and stuff out of your body and energy field. You do not need anyone or thing 'in' you to get guidance. That's one of the beautiful things about channeling. Clean, clear energy and vibration.
There is a way for you to get the guidance that you need everyday from your Spirit Guide. Get a Channeled Guided Meditation. (Ha! How Cool is that?!) Now, can you use any guided meditation? Oh, sure. But how much more would you get out of one made specifically for you? And, Channeled, at that?! Super Fantastic. Plus, you can use it [literally] for the rest of your life.
Click here to read all about it. So Fun!