To put it very plainly, yes, there are spirits, but they are not ghosts or aliens from other planets, either.
The Bible is very clear about what happens when someone dies. It is also very clear about other spirit creatures that do exist in addition to God, his Son Jesus Christ, and the millions of angels who reside in heaven with he and Christ Jesus.
The Bible says that in the last days, Satan and his demons will mislead many, and they certainly are. Why, they even pretend they are angels, or dead loved ones. They have been around earth since Adam and Even lived here.
If you only believe what you can see, then how can you believe in air, wind, electricity, or gravity? Because though you cannot see them, you can see their effects, just as you can see the effects of God's creations, and the effects the demons have on mankind.
The Bible also says we should not consult with spirit mediums or those who claim they can foretell future events or contact deceased loved ones. The reason given, is that these spirits who communicate, and many times rape, torture and mislead humans, are the very same spirits who came to earth in Noah's day and married the daughters of men, and produced offspring who were giants, or the "Nephilim."
The scriptures says that both man and animals are souls, not that they have souls. It also says that the soul that sins will die. It doesn't teach anything about a fiery, burning torturing place called Hell, either.
I usually give you many scriptures for these topics, but this time, I am just telling you like it is, and anyone who cares to learn more, can simply visit a page online,(http://www.jw.org) and get many answers to just about any question you may have about the Bible and what it really teaches, instead of the lies taught in practically every religion today.