You can still sell it, but you'll have to get the buyer to sign an agreement stating he/she knows the car needs to be inspected and assumes responsibility of any past registration fees. Attached to the title, there should be a vehicle liability release form. It should have a bunch of red text printed on it. You'll need to fill it out, get the buyer to sign it and turn it into the DMV within a week.
Not only will it help the car sell faster, it will also help you get more money for it if you'd just get it smogged and pay the registration fees. Any idea why the check engine light is on? If it's a cheap/simple fix, you should consider it. The fact that the top is leaking and the car hasn't been driven regularly is enough to turn any potential buyers away. Stuff like expired tags and check engine lights can be mistaken for signs of neglect. You want to make it as appealing as possible, otherwise don't expect to get more than 500 bucks for it