I have had what I think is a Geranium for a couple of years. It hasn't flowered in at least two. I trim it back every fall and new leaves generally shoot up. This year there are a couple of new leaves, but not much. Is it mean to throw it out and start fresh? I can't help but thinking of it as a living thing.
Barely Alive Geranium
Are you fertilizing according to package directions? Does it get enough light to bloom? Yes, it is a living thing, but sometimes it's best to end life if there is no hope and you've done everything possible to make it well. (My grandmother used to say, "Hit me a sure lick, don't let me suffer.") Geraniums can be prone to rusts and root damage. All plants have an expected life span. Maybe the time has come. However, if all the needs of the plant aren't being met, try giving it what it wants.
The article at this link has good information. Scroll to the "Indoor Culture" part and read through: http://www.ces.ncsu.edu/hil/hil-8504.html