Painting - airless sprayer broken

I got this Campbell/Hausfeld airless sprayer back in 2001 when I moved into my new home. IT worked well, painted the whole house with it. Paid around 350.00 at the Depot.
Before I put it away the last time I cleaned it well and used that storage
solution.
So I draged it out today and the thing doesnt prime, doesnt spray but the motor does work.
I was wondering if I should have run the thing a couple of time in bwtween uses?
Is it probably rusted out inside?
Probably would cost the same to fix as to buy a new one?
Would anyone have a clue as what might be the problem or what tends to break on these airless sprayers??
TIA

They are easy to fix and fairly indestructable. The motor always runs. Take the suction hose off of the front. Stick a pencil or? and push the carbide ball off of it's seat. They usually get stuck after storing. There is a light spring that keeps them in position. Turn it back on. It should have a rattling sound now and create a vacuum you can test by placing your palm against the opening (before reattaching the hose). If the suction ball is loose and not stuck the outlet ball is stuck or broken. This is the only part I consistantly had to replace and I have shot probably 1000 gal. with one. The outlet ball is taken out by backing out the brass 9/16" bolt on the top. when removed it is about 2&1/2" long and you can see the carbide ball and spring at the bottom of it. I use laquer thinner and a tooth brush to clean it out. There is a small pin on the bottom of pump head directly below the outlet valve. You can push the pin up to lift a stuck valve ball off its seat. Thats it. It's helpfull to turn the pressure knob all the way down, cycle it, then turn it back up. This bleeds air out of the hydraulic side. I have rarely seen the pressure knob go bad or the "prime/spray" knob assembly go bad. When storing squirt wd40 up into the suction area (with hose off) as this will help keep the ball from sticking.

I had a similar problem, ended up having a worn part( I found it after breaking everything down to find the problem),If Jeff's suggestions don't solve the problem try a rebuild kit. I got one from the local CH service guy and that solved the problem. Seems to me the rebuild kit was around 30$. You can check out their website, they have a listing of kits. its www.chpower.com
Good tip with the WD40 Jeff, I'll have to remember it.

Hey
thanks for all the posts - I just ended up taking to a place in the valley that fixes airless sprayers, cost me 90 bones but they did a thorough job and its running like a top now.
They gave me a good tip regarding what kind of solution to store inside... 50/50 mixture of motor oil and paint thinner.
This time I cleaned it really good and used the above storage soln. Shouldnt have any problems next time I need it, I hope.