Zenith 61" HD projection, model # IQD61W20

Hello everyone.  I have had my Zenith since 2001. I would like to know if anyone can tell me why the picture is darker and there seems to be a green ark or glow from bottom left corner to bottom right. It used to only do this a few times and snap out of it. I have also noticed that when it is in 16:9 ratio and the whole screen is white even for a couple of seconds it shuts off.  I would like to know what I should look & ask for when contacting a service tech. Any ideas on what and how much this could cost? I also had problems with it turning off and on by itself on start up. This was fixed by about 3 yrs ago while still under warranty. Luckily I had 5yrs extended warranty. But it just ran out in March 2006 so now it looks like I'm in trouble. Can anyone respond? I would appreciate it. I love the site, keep up the good work. Thank You.