Count Trapula,
What events have changed in your life that might make weight training less of a priority than in previous years?
Go back to the thoughts you were thinking when you were very motivated. What were they? What made having a great physique so desirable to you?
If you have a training partner who is just marking time, end that relationship and find a partner who is hungry. Go to a competition, watch, talk to people, light that fire.
Are you fat at all? If in addition to losing size you are putting on fat try this:
Homework assignment: Go to a local gym, put on some gym shorts that show your legs, not those baggy, knee length things, and stand at the counter greeting members with no shirt on. Do this with a smile and tell them how unmotivated you are! Say, "look, I am having trouble wanting to work out hard and eat correctly, hopefully exposing myself like this will force me to get my ass in gear and work out hard again!" This sounds stupid, yes. But I dare you to try it. Here is activity: Find a couple people from the gym who are in great condition, maybe friends, and go swimming at a pool or lake. Force yourself into situations where you'd like to look far better than you do now. Exercises like this do work. Take pictures of yourself. Do you like what you see? If not, post them on the fridge next to a few cut out pictures of people who look terrific. Set goals.
I hope some of these suggestions help you out.