Question
I have a cactus(not sure of the exact type), but within the last two years it started to grow arms.  There are six arms in total steming from what used to be the original.  I noticed yesterday the cactus started to lean sideways.  So I took a metal kabob stick and used it to prop the cactus up.  Now I am noticing the original stem is very soft, and the spines in that area are starting to fall off.  So I have stopped watering it.  What could this be?  I am planning on replanting it, as I believe it may have gotten to be to big for the pot.  And the pot I currently have it in does not allow for drainage, but this has never caused any problems before.

Answer
Your cactus has rot. It is a bacterial and/or fungal infection that cacti are susceptible to usually due to over watering.  By the time you see the signs of it, such as the softness, it is usually to late to treat.  What I suggest you do is cut off the arms with a sterilized knife, let them callous and start new plants. Dispose of the mother plant, the soil, and if you want to keep the pot, sterilize the pot.  The fact that the pot didn't allow for drainage is probably what started the rot, and it may have started months ago.  ALWAYS let cacti drain.

If you need help with starting new plants let me know.